Friday, December 18, 2009

Gene Based Pharmaceuticals and Gene Therapy

0 comments
New classes of products are being tested for use in humans and animals, all sharing genes as common targets. Products based on antisense technology directed toward neutralizing messenger RNA are probably being pursued most vigorously; gene therapy through permanent alteration of chromosomes might hold the greatest potential for treatment of diseases like cancer and for correction of genetic disease. The products depend either on classes of compounds that are related to nucleic acids (oligonucleotides and oligonucleotide analogues), on cells that have been genetically altered, of on viruses that bear appropriate nucleic acids.

For the large-scale production of nucleotides and nucleotide analogues, new molecular techniques must be developed. There are now no procedures for making substantial quantities of these types of materials in high purity and with appropriate chirality. Basic chemical and biochemical techniques must be developed for their preparation; new techniques (probably based on high-pressure chromatography) will be required for large-scale purification, and biological methods might be required for preparation of precursors and perhaps for formation of bonds.

For genetically modified cells and viruses, the usual techniques for mammalian-cell culture and molecular biology will be required, as will additional measures for safety and for economical, patient-specific production.

Tags: Bio Technology, Bio Genetics, Bio Process Engineering

Thursday, November 19, 2009

Understanding the Bio-remediation Process

0 comments
Bioremediation refers to the use of entire organisms (mostly soil microorganisms) or selected constituents of microbial cells (mostly enzymes) for chemical transformations. Bioremediation transforms a toxic substance into a harmless or less toxic substance. Ideally, the toxic substance is transformed into carbon dioxide and water. If the toxic substance contains a metal or a halogen, such as chlorine or fluorine, there will be additional side-products (perhaps the free metal atom or its ion or a halide ion). Mineralization is the term used to describe the complete degradation of a chemical substance to water and carbon dioxide. Bioaugmentation, another frequently used term, involves the deliberate addition of microorganisms that have been cultured, adapted, and enhanced for specific contaminants and conditions at the site.


Microorganisms used in bioremediation include aerobic (which use free oxygen) and anaerobic (which live only in the absence of free oxygen). Aerobic microbes have been the organisms of choice for degrading hazardous wastes.

Bioremediation is practiced in two modes - in situ and ex situ. In situ bioremediation involves the use of microorganisms to degrade wastes at the site (both on and below the surface) and avoid excavation of contaminated soil and transfer to different locations. Surface remediation is used to treat the top parts of the soil through aeration by the addition of microorganisms, nutrients, and water. Subsurface bioremediation uses microorganisms already in the soil and groundwater and adds oxygen and nutrients. Ex situ treatment involves the excavation of contaminated soil and its transfer to appropriate treatment sites, i.e., bioreactors. The contaminated soil is aerated and treated with nutrients to provide an active environment for the microorganisms of choice. Treatment continues until the soil is sufficiently clean and can be returned to the site. Ex situ techniques are varied but can involve slurry-phase treatments that combine contaminated soil or sludge in bioreactors or solid-phase treatments that involve placing contaminated soils in lined treatment beds. Bioremediation of water or leachate includes treatment with special bioreactors or filters that contain an active film of microorganisms. The choice of method involves many factors, including the contaminant, the site, and the costs that can be borne. Ex situ treatment is usually very expensive. Most often, the microorganisms are expected to reproduce in situ.

Tags: Bio Technology, Bio Genetics, Bio Process Engineering

Sunday, August 30, 2009

Futuristic use of Transgenic Animals & Transgenic Plants

0 comments

Transgenic Animals:Transgenic animals are being developed for a wide variety of applications. In the near future, transgenic animals will be used increasingly in safety evaluation of new pharmaceuticals and accelerating their regulatory approval. The feasibility of producing human pharmaceutical proteins in the milk of transgenic livestock has been established.


As an alternative to cell-culture systems, such livestock appear to be appealing because of high volumetric productivity, low operating costs, capability of posttranslation modification of proteins, and potential for expansion of the producing organism. Bioprocess engineers face numerous technical challenges in converting a transgenic mammary gland system into a commercial prototype for large-scale manufacture of high-market-volume proteins, including the following:


1) Purification techniques for obtaining high-purity proteins that must be recovered and fractionated from a complex mixture of fats, proteins, sugars, and ions, some of which are in colloidal form.


2) Optimization of product stability during recovery.


3) Instrumentation to characterize posttranslation modifications made by the mammary gland "bioreactor."


4) Development of on-line sensors to monitor changes in bioactivity of products during purification.


5) Bioseparations of milk proteins.

In the longer term, transgenic animals might provide a source of tissues and organs for use in transplantation patients. Bioprocess engineering will be needed to design novel equipment to maintain, purify, and store the living tissues without affecting viability or graft response.


The hurdles to be surmounted in developing the necessary genetic tools for systematic pathway engineering are substantial, but basic research at the molecular level will continue to provide improved production strains and novel products, and continued interest in the fundamentals of bioprocessing of milk will help to define separation strategies for this complex biological fluid.

Transgenic Plants:Transgenic plants are capable of generating specialty chemicals or other bioproducts. Special bioprocessing capabilities will then also need to be developed for extracting, concentrating, and purifying such products from plant tissue. This sector of bioprocess engineering might also be important to the prospects of expanding crops or developing new varieties that are rich in fermentable carbohydrates, which are readily used as feedstocks for large-scale manufacturing of specialty and industrial chemicals.


Transgenic tobacco plants have been developed to produce monoclonal antibodies identical in function with the original mouse antibody. Other proteins produced in plants are human serum albumin and enkephalins. Processes to recover and purify proteins from plant-cell extracts will be needed if such systems are commercialized.


Tags: Bio Technology, Bio Genetics, Bio Process Engineering


Understand the Basics of Metabolic Engineering

0 comments

A powerful new approach to product development is the creative application of fermentation technology and molecular biology for "metabolic engineering." Examples of metabolic engineering for heterologous-protein production include deletion of proteases that eliminate product and production of factors that facilitate product maturation and secretion. For protein production on an industrial scale, metabolic engineering could be useful in shifting metabolic flow toward a desired product, creating arrays of enzymatic activities for synthesis of novel structures, and accelerating rate-limiting steps. Metabolic engineering has recently been used to increase the efficiency of nutrient assimilation (increasing the growth rate), improve the efficiency of ATP production (decreasing nutrient demands), and reduce the production of inhibitory end products (increasing final cell densities).

Central to molecular modification of multigene pathways, such as those involved in antibiotic production, is the development of new vectors and transformation procedures and other tools of molecular biology. Another important discovery in metabolic engineering is the isolation of positive-control genes that regulate production of secondary metabolites. Positive regulators have been found in biosynthetic gene clusters for actinorhodin, bialophos, streptomycin, and undecylprodigiosin, all of which are Streptomyces products.

Genes encoding the converting enzymes D-amino acid oxidase and cephalosporin acylase were cloned from Fusarium and Pseudomonas, respectively, into the fungus Acremonium chrysogenum. Expression of this "artificial" antibiotic biosynthetic pathway was confirmed by analysis of transformants that synthesized and secreted detectable amounts of 7- aminocephalosporanic acid.

In addition to classical mutation, new tools have become available for genetic manipulation of important producers of natural products, such as Streptomyces. The ability to clone and manipulate biosynthetic genes for antibiotic production, regulatory genes for improved synthesis, and genes from primary metabolic pathways that contribute to secondary biosynthetic pathways can facilitate construction of strains that have substantially altered metabolic properties. In addition, the cloning of heterologous genes into bacterial hosts has generated strains that can produce compounds that are foreign and even
Deleterious to cell physiology.

Tags: Bio Technology, Bio Genetics, Bio Process Engineering


Know the Basics of Protein Engineering

0 comments

Advances in molecular biology have provided researchers with the opportunity to develop increasingly rational approaches to the design of therapeutic drugs. This technology, when used with computer-assisted molecular modeling, is called protein engineering.


Protein engineering combines many techniques, including gene cloning, site-directed mutagenesis, protein expression, structural characterization of the product, and bioactivity analyses; it can be used to modify the primary sequence of a protein at selected sites to improve stability, pharmacokinetics, bioactivity, and serum half-life. A second application of protein engineering is the design of hybrid proteins that contain regions that aid separation and purification. That is achieved by introducing, next to the structural gene for the desired product, a DNA sequence that encodes for a specific polypeptide "tail."

The tails can be inserted at the N or C terminal of the protein to yield a fusion protein with special properties that facilitate separation. Such genetic modifications can be designed to take advantage of affinity, ion-exchange, hydrophobic, metal chelate, and covalent separations. The special properties of fusion proteins allow crude microbial extracts to be passed over an adsorbent that binds specifically to the tail, so that the desired product is retained and contaminants pass through. After elution and treatment to remove the tail, the product is purified further by standard methods, such as size-exclusion chromatography or high-performance liquid chromatography (HPLC).


Tags: Bio Technology, Bio Genetics, Bio Process Engineering


Challenges to Isolation and Purification of Proteins

0 comments

Isolation generally denotes the separation of the product from the bulk of the producing organism. The disposition and state of the expressed protein affect the isolation procedure. For mammalian cells and some E. coli, Streptomyces, Bacillus, and yeast products, the protein is released from the cell into the surrounding medium, and isolation is effected by a solid-liquid separation step, usually centrifugation or microfiltration or ultrafiltration. If the product has aggregated either in the cytoplasmic or periplasmic space, isolation is more involved. Generally, the cell is first lysed by mechanical, chemical, or enzymatic treatment (or a combination). In some cases, the more dense aggregate can be separated by centrifugation from most of the soluble and insoluble cell components; in other cases, the aggregate is first solubilized while still in the soluble protein mixture.

Purification of the protein is a critical and often expensive part of the process. It might account for 50% or more of the total production cost. Purification has several objectives: to remove contaminating components from the host organism, i.e., other proteins, DNA, and lipids; to separate the desired protein (or family of proteins) from undesired variants of the desired protein; to remove and avoid the introduction of endotoxin; to inactivate viruses; to obtain required yields at acceptable cost; to avoid chemical or biochemical modification of the protein; and to make the process consistent and reliable. In some cases, the first and additional objective is to fold the protein into its desired conformation.

The most common individual operations are centrifugation, filtration, membrane separation, adsorption separation, and chromatography.

The difficulty of separation can often be decreased by changing the organism or culture conditions to produce a more uniform protein. However, it is still necessary to combine a series of purification steps each of which separates according to a different principle. Ultrafiltration steps are often used between separation steps to concentrate the protein solution or to make the buffer solution compatible with the next separation step. The final steps are designed to place the purified protein in the solution used for the product form.

The complexity of the individual purification steps and the need to be able to integrate them into a manufacturing system translate into a major opportunity for bio-processing engineering as the process moves from the bench to the plant. Research and development in purification, scaleup integration, and system design will continue to have high priority.

Tags: Bio Technology, Bio Genetics, Bio Process Engineering


Bio-Processing of Renewable Resources & its challenges

0 comments

Most of the applications and potential applications of bioprocessing related to renewable and nonrenewable resources involve large-scale operations and products of relatively low value. The most abundant renewable material is lignocellulose. Wood, agricultural residue (corn stover, straw, etc.), plants grown deliberately for biomass (such as hybrid aspen), and recycled pulp fiber are the main sources of lignocellulose. Its largest industrial use is in making pulps for paper and other fiber products; second is the use of wood directly in construction.

Key Technical Challenges in Bioprocessing of Renewable Resources are as under:

1) To develop inexpensive cellulose pretreatment and saccharification processes effective with lignocellulosic materials on large scale with environmentally compatible methods.

2) To develop fermentations capable of converting pentoses to value-added products at yields, rates, and extents similar to those obtained for glucose with yeast and to increase product concentrations achievable in both hexose and pentose fermentations.

3) To develop more efficient separations for recovering fermentation products, sugars,and other dissolved materials from water, i.e., lower cost of separating water from product in fermentation broth.

4) To develop processes for large-scale inoculation, control, and propagation of microorganisms in surface culture (e.g., treatment of wood chips and bioremediation of soils) and solid substrate fermentation.

5) To increase knowledge of combinations of chemical, biochemical, and microbial transformations that result in value-added nonfood products from starch and cellulose.

6) To improve fractionation methods for separating oil, starch, and fiber components during corn milling to obtain higher co-product values with lower capital investment.

Tags: Bio Technology, Bio Genetics, Bio Process Engineering


Understanding Bio-Process Engineering

0 comments
Bioprocess engineering is the subdiscipline within biotechnology that is responsible for translating life-science discoveries into practical products, processes, or systems capable of serving the needs of society. It is critical in moving newly discovered bioproducts into the hands of the consuming public. The bioprocess engineer has many missions. Although the most visible today is the production of biopharmaceuticals, bioprocess engineering also has a major role in the existing fermentation industries responsible for the production of ethanol, amino acids and other organic acids, antibiotics, and other specialty products.

Bioprocessing in space presents unique opportunities, particularly in bioregenerative life support and as a research platform for the study of new types of manufacturing processes.


Bioprocessing for protection and beneficiation of the environment represents another large and important opportunity. Biological processes could offer alternatives to environmentally polluting or fossil-fuel-consuming manufacturing processes and could help to remove toxic pollutants from industrial and municipal wastes. Bioremediation's promise is in its potentially lower cost, compared with other types of technology for cleaning up the environment.

Role of bio-process engineering:
The role of bio-process engineering in the successful commercialization of biotechnology is not fully understood by our national government, industrial, and academic leadership. That is in large measure because first-generation biopharmaceutical products have been successfully produced with only secondary concern for costs of manufacturing. However, products now under development will require novel techniques and more efficient and economical processes. Hence, our participation in the expanding bio-products market will necessitate an expanded role of bio-process engineering. This is all the more important because bio-process engineering could have a profound effect on the existing fermentation industry.

Bio-process development for biopharmaceuticals involves all aspects of generating a safe, effective, and stable product. It begins with the biological system, continues with product isolation and purification, and finishes when the product is placed in a stable, efficacious, and convenient form. The product is initially derived either directly or indirectly from a living organism. Thus, process development starts with the development of the biological system. It is usually a living organism that expresses the desired protein; but it might be an enzyme for protein modification or an antibody for immunoaffinity purification. RDNA and hybridoma technology allow the biological system to be optimized for maximal formation of the product, for facilitation of downstream processing, for high product quality, and for improved interaction with the production equipment. In this phase of bio-process engineering, many disciplines must be applied, including molecular biology, genetics, biochemistry, analytical chemistry, and bio-process engineering. Thus, engineers become full partners with experts trained in the bioscience disciplines in developing and scaling up manufacturing technology for biopharmaceuticals.


Tags: Bio Technology, Bio Genetics, Bio Process Engineering

Wednesday, August 5, 2009

Understanding various concerns of Human Genome Project

0 comments
The importance of the Human Genome Project has raised many concerns, both biological and ethical. These questions are being addressed as the information generated by the project is being processed and used by people worldwide.

1) Privacy and confidentiality of the genetic information: Who owns the genetic information?


2) Right to use the genetic information by insurance companies, employers, courts, schools, adoption agencies, and so on: Who should have access to individual genetic information and how should it be used?

3) Psychological impact and stigma attached to an individual's genetic differences: How does personal genetic information affect an individual and society's perception of that individual? How does genomic information affect members of minority communities?

4) Reproductive issues, including informed consent for complex and potentially controversial procedures, use of genetic information in reproductive decision making, and reproductive rights: Do health-care personnel properly counsel expectant parents about the risks and limitations of genetic technology? How reliable and useful is fetal genetic testing? What are the larger societal issues raised by new reproductive technologies?

5) Clinical issues, including the education of doctors and other health service providers, patients, and the general public in genetic capabilities, scientific limitations, and social risks, including implementation of standards and quality-control measures in testing procedures: How will genetic tests be evaluated and regulated for accuracy, reliability, and utility? (Currently, there is little regulation at the federal level.) How do we prepare health-care professionals for the new information relating to genetics? How do we prepare the public to make informed choices? How do we as a society balance current scientific limitations and social risk with long-term benefits?

6) Uncertainties associated with genetic tests for susceptibilities and complex conditions (e.g., heart disease) linked to multiple genes and environmental interactions: Should testing be performed when no treatment is available? Should parents have the right to have children tested for adult-onset diseases? Are genetic tests reliable and interpretable by the medical community?

7) Conceptual and philosophical implications regarding human responsibility, free will versus genetic determinism, and concepts of health and disease: Do people's genes make them behave in a particular way? Can people always control their behavior? What is considered acceptable diversity? What is the line between medical treatment and enhancement?

8) Health and environmental issues concerning genetically modified (GM) foods and microbes: Are GM foods and other products safe to humans and the environment? How will these technologies affect developing nations' dependence on the West?

9) Commercialization of products including property rights (patents, copyrights, and trade secrets) and accessibility of data and materials: Who owns genes and other pieces of DNA? Will the patenting of DNA sequences limit their accessibility and development into useful products?

Tags: Bio Technology, Bio Genetics, Genetic Engineering

History of Human Genome Project

0 comments
Scientists are still far from identifying and characterizing all the proteins in the human body. However, incredible strides have been made to provide a foundation for protein research. This reaches to the source of proteins and ultimately the source of life. This foundation is laid by deciphering the entire genome sequence, or DNA (gene) sequence of an organism. Beginning with bacteria, microscopic worms, and yeast, scientists and computational biologists have expanded DNA sequence information to include certain animals and plants. The ultimate goal of DNA sequencing is the human genome. This genome sequence would allow the understanding of the basis of human life by identifying the order of DNA nucleotides. To accomplish this goal, many groups have come together to work on the Human Genome Project.

The sequencing of the human genome, which is finding the order of the more than 3 billion nucleotides (A, T, C, and G) in the human chromosomes, is being accomplished by two independent groups of scientists. The two versions of this sequence were published in the magazines Nature and Science in February 2001. One group, formerly led by Craig Venter, is Celera Genomics, of Rockville, Maryland, a company started in 1998. The other research group is the result of a consortium of public agencies with laboratories in several countries.

The sequence of the human genome carried out by the public sector, now led by Francis Collins, has a budget of more than $3 billion. The major sponsors were the U.S. Department of Energy and the National Institutes of Health (NIH), as well as the Wellcome Foundation of England. The current map covers about 95 percent of the human genome and has been found to be 99.96 percent accurate. This work has revealed, in a surprising way, that the human genome only has about 30,000 genes instead of 70,000 to 140,000, according to previous estimates. With a DNA sequence of over 3 billion base pairs (bp) and considering the average gene size of 3,000 bp, it is estimated that only 3 percent of the human genome actually codes for some protein. This means that about 97 percent of the human genome has seemingly no coding function; that is, most of the nucleotide sequences in human DNA do not code for genes. This nonfunctional portion of DNA has, for lack of a more accurate term, been called "junk DNA," and its function and purpose have yet to be understood. More important, the data from the Human Genome Project has also revealed that each human being, independent of apparent differences, is about 99.9 percent identical to any other person.

With so much interest and emphasis on the Human Genome Project, what are the practical applications of the sequence of the human genome? The information will help in the early diagnosis of disease, an understanding of the predisposition to genetic diseases, and in genetic counseling, for example. For instance, the sequence of the human genome allows geneticists to understand why certain people have a predisposition to heart disease, and it will eventually lead to the development of new drugs specifically developed to combat the cause of disease and not the symptoms alone. Sequencing the genome will make available basic scientific knowledge for the development of gene therapies for incurable diseases, such as diabetes, muscular dystrophy, cystic fibrosis, Parkinson's disease, and Alzheimer's disease.

By the beginning of 2002, geneticists had already isolated about 13,000 human genes and learned about their functions, including those that code for eye color, circulatory proteins, and genes that when mutated cause a predisposition for developing breast cancer and prostate cancer. All this complex information is contained in each and every cell of the human body. If it were possible to stretch out the incredible amount of information contained in the DNA of all the chromosomes in a single human cell, it would reach about seven feet. If the DNA of all the cells of the human body were stretched out and aligned, it would be enough to cover the distance from Earth to the moon about 8,000 times. Incredible packaging mechanisms allow this information to be stored within each tiny cell.

Tags: Bio Technology, Bio Genetics, Genetic Engineering

Understanding Engineering Genes

0 comments
Once the DNA has been obtained, it is necessary to cut the DNA into pieces to be used for the engineered gene. Restriction enzymes are used for cutting the DNA at specific sites. Most restriction enzymes cut the DNA into diametric fragments, as opposed to symmetric fragments. That cut leaves the DNA double helix with a small sequence of nonpairing bases that overhang on the end. These regions of DNA are generally used for ligation, or joining with other DNA fragments. DNA fragments cleaved with a single restriction enzyme or with complementary enzymes can be ligated to each other because the overhanging regions are complementary and will bind together. The ligation of fragments is facilitated with addition of the enzyme DNA ligases. The true art of genetic engineering is putting together the parts of puzzle, where each DNA fragment must be placed in right order and orientation so the gene is functional. As scientists know the sequences of genes encoding important traits or proteins, the information is used to engineer genes that can be used in a variety of applications.

Genetic engineers are able to manipulate tiny pieces of DNA with enzymes to create new genes and DNA sequences used in biotechnology. Relatively simple tools in a small laboratory are needed for these engineers to practice their craft. The products that result from these methods can then be used in many applications of biotechnology.

Tags: Bio Technology, Bio Genetics, Genetic Engineering

What is Central Dogma of Genetics?

0 comments
The genetic material of any organism is the substance that carries the information that determines its life cycle and its characteristics. There is a procedure by which this genetic material is used in living processes; this is the central dogma of genetics. Before the development of modern genetics, it was commonly believed that the substance responsible for heredity was a protein. Once DNA was recognized as the genetic material, the central dogma was established. This states that the information contained in DNA is translated into protein through the processes of transcription and translation. The protein is then used in all life processes, from cell division to electron transport in photosynthesis. For this to occur, DNA is copied (transcribed) into mRNA, and the mRNA is used as template for production of the protein in a process called translation. The message coded by the mRNA sequence gene is translated into a sequence of amino acids, the basic components of protein. Cells cannot produce a protein by simply aligning amino acids; they need to use an RNA template. Additionally, the use of an intermediate mRNA template in protein synthesis reduces the risk of damage to the DNA that can occur from repeated use. Additionally, the central dogma postulates that the intermediate mRNA molecule, a direct copy of DNA, can be used repeatedly in protein synthesis.

Main points of the central dogma are as under:
1) Genes are made of DNA.
2) Genes carry information about structures and biological functions, coded by nucleotides (A, C, G, and T).
3) The genetic information is converted in an mRNA molecule.
4) The mRNA defines the number, type, and order of amino acids in proteins.
5) The protein structure is determined by the linear order of amino acids.
6) The three-dimensional protein structure defines its biological function.

Tags: Bio Technology, Bio Genetics, Genetic Engineering

How do we Manipulate Genes?

0 comments
Before beginning any genetic engineering project, it is necessary to obtain a reasonable amount of relatively pure DNA, which is then cut and ligated to build the new gene. Today, several companies make DNA extraction and purification kits, making the genetic engineering process much simpler. The basic procedure requires the releasing of the DNA from the cells and purification of the DNA to be used in the experiments.

In a typical extraction and purification procedure for plasmid DNA, bacterial cells with the desired plasmid are lysed (broken up) under alkaline conditions and the crude lysate (remains of the cells) is purified using either filters or centrifugation. The lysate is then loaded onto an apparatus where plasmid DNA selectively binds under appropriate low-salt and pH conditions. RNA, proteins, metabolites, and other low-molecular-weight impurities are removed by a medium-salt wash, then plasmid DNA is released in high-salt buffer. The DNA can then be concentrated and desalted for genetic engineering uses.

General Steps for Gene Manipulation are as under:
1) Grow the bacteria in liquid culture.
2) Centrifuge the bacterial suspension to concentrate the bacteria.
3) Discard the supernatant (the liquid part that remains above the pellet).
4) Resuspend the bacteria pellet in a solution with RNAse (enzyme that degrades RNA).
5) Add a buffer to promote an alkaline lyse of the bacteria.
6) Neutralize and adjust the saline conditions of the suspension with the buffer.
7) Centrifuge to separate proteins and other impurities.
8) Adsorb the plasmid DNA onto a membrane by filtration.
9) Rinse the membrane with a solution containing ethanol.
10) Elute plasmid DNA from the membrane with EDTA, a chemical substance that preserves the integrity of DNA.

Tags: Bio Technology, Bio Genetics, Genetic Engineering

What are Viruses?

1 comments
Viruses are microorganisms in the gray area of what is living and nonliving. Viruses are made of a protein envelope, which surrounds the genetic material (DNA or RNA). Although viruses have their own genetic material like many other living organisms, they do not possess the capacity to reproduce by themselves. For that, they need to use the machinery of living cells to produce a new virus.

The viruses that live in bacteria are called bacteriophage. They inject their DNA into bacterium, leaving their protein envelope outside. Inside of the bacterium, the virus is a filament of nucleic acid that contains coded information for the synthesis of new virus particles, which can be released with the bacteria lyses. The genetic engineering came about from the observation of how viruses use cells of other organisms or bacteria to express their own genes. In that sense, the viruses can be considered genetic engineers. One of the first experiments of genetic engineering was carried out using a bacteriophage as a true Trojan horse, to introduce DNA from other organisms into the bacterium.

One of the requirements for genetic engineering experiments is the production of DNA fragments that contain the desired information. At the beginning of the molecular biology era, DNA used to be cleaved with vibration by ultrasound waves. One of the difficulties that scientists faced in those experiments was the random fashion in which the DNA fragmented. In 1970, however, Dr. W. Arber discovered that bacteria themselves possess a mechanism to specifically cut DNA at certain sequences. Bacteria produce proteins called restriction enzymes that cleave the DNA at specific recognition sites. It was only after the discovery of the restriction enzymes that genetic engineering became a reality. The restriction enzymes were developed as a defense mechanism of bacteria against viruses.

Viruses inject DNA into bacteria and use their bacteria as a mechanism for reproduction. The bacteria, however, develop a mechanism that fragments the exogenous DNA using restriction enzymes. The restriction enzymes recognize the foreign DNA by means of certain specific nucleotide sequences. Different enzymes recognize and cut the DNA at different sites. Using this knowledge, restriction enzymes became essential tools for the genetic engineer to cut DNA into fragments and build new genes. Hundreds of different restriction enzymes exist, many of which are frequently used in biotechnology.

Tags: Bio Technology, Bio Genetics, Genetic Engineering, Virus

Wednesday, June 17, 2009

Improving Human Race through the science of Eugenics

0 comments
Eugenics seeks the genetic improvement of the human race through selection. This idea became more prominent in the beginning of the 20th century and had another great push during World War II. One of Hitler's main objectives was the purification of the Aryan race.

According to the theory of evolution, developed by Charles Darwin in 1859, more "fit" individuals are capable of leaving a larger number of offspring. However, less fit individuals tend to leave fewer descendants. Therefore, over many generations, genes of less adapted or "inferior" individuals are gradually eliminated from the population. Darwin called this process natural selection.

Due to the use of medicines and improved medical procedures in the last few centuries, man has evaded natural selection. A classic example is the Cesarean section procedure for childbirth. Women that would otherwise die from natural childbirth can now produce offspring. Therefore, today, genes for body shape that prevent natural deliveries are retained in the population.


Natural selection for this trait still exists in indigenous populations that do not have access to modern medicine, but this is the exception and not the rule. In some way, less adapted people with low physical resistance, predisposition for genetic diseases, and so on, continue to leave offspring with the help of modern medical resources. How many of us would not be here if medical resources were not available?

Proponents of eugenics argue that the human species is accumulating bad genes because man has a slow natural selection. Others argue that people need a license for many activities, such as driving, hunting, and fishing, but not to procreate, and therefore the government should also control procreation. In China and India, the government regulates population growth. This is a quantitative and not qualitative control. Some people argue that there is sexual discrimination in those two countries, and that boys tend to be preferred because they can bring larger revenue for their family.

The next 20 years will bring many changes in human behavior, and one can imagine that a revolution could take place that will transform the world. Comparing the world today and that of 50 years ago, no one would think that eugenics could be an issue again. Some of the most despicable human acts were performed in the name of the Aryan race purification. Until 1945, eugenics was taught in many important universities around the world, and the compulsory sterilization of inferior people was relatively common in several countries. There are reports of sterilization of 20,000 people in the United States, 45,000 in England, and 250,000 in Germany during the first half of the 20th century. Eugenics turned public opinion against government intervention in citizens' reproductive choice, and today, compulsory sterilization is only conceivable in the minds of fanatic eugenists. However, with world overpopulation and a growing shortage of resources, many people are afraid that population controls could become a reality again.

Currently, it is difficult to imagine that collective sterilization would be used again, but as genetic tests become routine, it is feared that a new wave of sterilization and abortion could take place, not because of mandatory enforcement, but because of pressure resulting from genetic counseling. Abortion based on genetic counseling is already a reality in countries where it is legal. However, is it right to discriminate against genetic defects or weaknesses, even if it is in the womb? Isn't life just as precious? History has shown that the memory of people is short and that history is cyclical.

With an uncertain future ahead, it seems opportune to recognize that genetic tests and new forms of human reproduction will be part of society from now on. In this scenario, the best alternative seems to be drawing strength from family and moral and religious principles.

Tags: Bio Technology, Bio Genetics, Bioethics

Imagine what hapens when human cloning becomes a reality

0 comments
Although human cloning has not been done yet, it is believed that it will happen in a matter of time. Since the Dolly sheep cloning in 1997 by Dr. Ian Wilmut at the Roslin Institute in Scotland, the technique has been advanced with many other mammals (monkeys, cows, cats, pigs, etc.). Many countries, however, are passing laws that forbid human cloning. However, some research groups, mainly in infertility clinics, have indicated their interest in human cloning. Although it is technically possible to clone humans, there are several scientific reasons for not doing so.

Beyond the risks for the pregnant mother and for the clone, a series of ethical issues has been raised in relation to human cloning:

1) Would clones have a soul?
2) How would clones relate in a family setting or in public settings?
3) What would be the limits of paternity and social responsibility to clones?


Some ethicists would argue that cloning violates a child's right to an open future. A cloned child would feel the pressure to become similar to his or her biological donor.


Ethical issues will be raised as society discusses and understands the implications of human cloning. Consider, for example, that human cloning was a reality today.

In this scenario a child could have a variable number of parents, from just one to as many as five:
1) One parent: This would be the case when a woman has been cloned, serving as the egg donor, the donor of somatic cells, and the surrogate mother.
2) Five parents: This would happen when the clone has the following parents:
a) Biological father (somatic cell donor)
b) Biological mother (egg donor)
c) Social father (adoptive)
d) Social mother (adoptive)
e) Surrogate mother

Cloning is a great challenge for society, and moral values certainly will deeply change in the 21st century.

Finally, as humans are not just biological beings, biotechnology should consider its limits on the basis of spiritual values. For example, religious conversions produce profound behavior transformation without any genetic modification. This fact reinforces the idea that human behavior is not just a matter of genes or the environment in which the individual develops. An individual, despite possessing superior genes, can be arrogant and behave irresponsibly in relation to society.

Tags: Bio Technology, Bio Genetics, Bioethics

Can we have our privacy in the era of Genetic advancements

0 comments
Privacy and confidentiality are one of our most valued possessions. Soon, it might not be possible to hide from society our weaknesses, limitations, and genetic deficiencies. The individuality of each human being is being unmasked.

The completion of the first version of the Human Genome Project, announced in February 2001, unveiled the genomic sequence of the almost 3.2 billion letters of our chromosomes. This announcement also generated discomfort and fear. The revelations of the deficiencies and predispositions coded by human gene sequences are an unsettling idea for many people. The knowledge of the human genome sequence will make possible the diagnosis of several diseases even before their onset. The association between genes and genetic diseases not only affects patients, but it also raises legal and economic issues for society.

In some countries, like Great Britain, the population of some regions has voluntarily donated DNA samples for establishing a genomic database for criminal use. In that country, the ethical perception is that DNA donation for genomic databases is not an invasion of an individual's privacy. In the United States, the situation is completely the opposite: The great majority of the population has a much stronger sense of individuality and so opposes the idea of genetically exposing themselves. However, some genomic databases have been made mandatory in the United States, such as the one at the FBI. In some states, inmates involved in sexual crimes, murders, and other violent crimes have been required to have their DNA profile included in genomics databases. The fear of many people in relation to the loss of their genetic privacy is that the DNA information could be used for discrimination in employment situations or for health and life insurance.

Some geneticists believe that a DNA profile will not only be used to solve crimes, but also to prevent them. They argue that violence is a genetically transmitted trait. Dutch scientists studied a family in the Netherlands with male individuals with outstanding rates of aggressiveness and rape over five generations. The men were found to carry a genetic defect that causes a deficiency of the enzyme serotonin in their brains. Serotonin is a neurotransmitter related to behavior, humor, and personality in humans. Perhaps this is evidence for the existence of genes associated with violence and other antisocial behavior.

A correlation has also been found between atypical levels of serotonin and dopamine with violent behavior and suicide in different studies. The levels of the neurotransmitter are regulated by genetic and environmental factors as well as the interaction between the two factors. The environment is a broad term referring to nongenetic factors contributing to the trait of interest. This can include upbringing, relationships, lifestyle, and other less tangible influences on behavior or health. Current attempts to link violence to genes are more sophisticated and are applied to individual cases and not to population groups. It is believed that, in the near future, genes for violence or dishonesty will be identified, just like the genes related to cancer and other diseases. In reality, even if all the complex human traits like intelligence, violence, honesty, anxiety, and friendliness are mapped and sequenced, they will remain misunderstood for a long time because the understanding of the human mind is still so limited.

Even if the existence of a gene for violence were confirmed, would it be ethically correct to label a child as prone to violence? Would the simple knowledge of that information alter the isolation patterns of society in relation to a carrier of that gene, inducing him or her to become violent? It should be recognized that the manifestation of most traits results not only from genes, but also environmental influence during an individual's life.

Today there are genetic tests for the detection of genes that predispose an individual to the following diseases: sickle cell anemia, Down's syndrome, Huntington's disease, muscular dystrophy, cystic fibrosis, Tay-Sachs, colon cancer, breast cancer, Alzheimer's disease, and multiple sclerosis. The number of diseases for which genetic tests are available continues to grow.

The inclusion of genetic tests results in information on an individual's medical record that could have serious effects in his or her life. Health or life insurance companies might refuse coverage for medical treatments under the allegation of a pre-existing condition. Today, pre-existing conditions only apply to diseases that have already been manifest in the individual; in the future, this might be extended to include the presence of genetic factors linked to specific medical conditions.

Large corporations routinely request intelligence and personality tests for prospective employees. Some people fear that, in the near future, genetic tests will be routinely requested prior to employment. Today, some companies already use genetic tests to identify employees who are sensitive to chemical products used in the work environment. Those companies have argued that the genetic tests are used only to protect their employees from risks related to work, and obviously, to eliminate the risk of being sued for damages in the future. According to the companies, they do not use genetic tests for selection purposes. In the future, companies could opt to increase the number of genetic tests that are mandatory for recruitment. Such tests might reveal personality patterns and could possibly be used for discriminatory means.

Biotechnology has opened the door to our lives, and questions of genetic privacy still remain to be answered. It is now possible to know more about our genetic makeup, but is that necessarily good? This raises many questions about the use of the enormous amount of information that has been made available.

Tags: Bio Technology, Bio Genetics, Bioethics

Genetic Engineering & Bioethiocs

0 comments
Science has proven that DNA is the basis of heredity in nearly all living creatures. It is unusual to think that the same molecules that make a fungus a living creature are also similar for human life. The science of genetics has even found gene sequence coding for specific enzymes and proteins that are virtually identical in humans, plants, and microorganisms. Experiments have shown that genes from one species can be manipulated and expressed in another species.


With the advances from biotechnology in agriculture, medicine, and other areas, genes from highly diverse organisms have been transformed into other species to obtain the expression of a certain trait. An often-cited example is again that of Bt corn. A gene from a soil-borne bacterium was engineered into corn to provide resistance to a devastating insect species. For many, this is not ethically wrong, but others find inherent problems in the use of genes across species. It is a basic issue with the science of biotechnology: whether or not our knowledge of DNA and genetics should allow us to manipulate organisms that are not naturally compatible. Many believe that such genetic manipulation is beyond the realms of responsible and moral science. Does such DNA manipulation change the inherent properties of corn or any other organism, or does biotechnology serve to expand the frontiers of life?

This question is one of the basic ethical arguments behind biotechnology and is actually just the beginning of the many ethical questions that can be directed at this science. Despite arguments about the moral justifications of basic genetic engineering, scientists continue to develop products using advanced methods of gene manipulation. However, many cultures and traditions might be affected by such engineering techniques. For instance, those of the Jewish faith abstain from the use of pork, as it is traditionally considered unclean. What would be the ethical implications of using swine genes in a medicine, plant, or other product? Would it compromise the faith of one who abstains from pork? Such examples can be expanded to include many other scenarios in which this encounter of science with tradition could occur. The issue leads to the questioning of many long-held traditions and beliefs. Perhaps life is simpler than previously thought, and advances in genetics and biotechnology allow us to understand how life is simply contained in the ordered chemistry of DNA. This leads to the importance of public awareness of the applications of biotechnology and must also be included in a debate about ethical implications related to this expanding science.

Finallly where do we move from here?
The fine line between right and wrong, or between ethically acceptable and ethically unacceptable behavior, is a tremendous part of bioethics. If it were possible to define those limits or present a rule of thumb to guide ethically correct decisions, it would certainly be mentioned here. However, it seems that many of the ethical cases related to biotechnology have no clear right or wrong and should be judged on an individual basis. Ethical considerations relating to the many facets of biotechnology should not be something that is only discussed at a company board meeting or within the committee rooms of governing organizations. Many of these new technologies will affect everyone in the near future, and it is important to recognize the many considerations involved in biological sciences. Biotechnology is advancing and making progress on the major factors that limit the lives of billions of people. Solutions to the problems of hunger, disease, pollution, and others are being found using the science of biotechnology, yet many are apprehensive about the technology or fear the technical nature of the science.

Despite the greatest efforts, balanced arguments that will satisfy everyone are impossible to find. The first step for anyone is to become educated in the background, the science, and the applications of biotechnology. It is then important to be informed about how biotechnology affects the risks, benefits, and moral implications associated with superior health care, enhanced crop production, and environmental improvement. This knowledge must be used to make informed and sound judgments, so that opinions are based on fact and study, and not on emotion, hype, or fear. Ultimately, each individual must take the essential steps to understand biotechnology.

Tags: Bio Technology, Bio Genetics, Bioethics

Know the Therapeutic Cloning

0 comments
Most people and the scientific media were surprised with the publication of the article "The First Human Cloned Embryo" in the magazine Scientific American in November 2001. Even the most optimistic followers believed that experiences with human cloning would not produce results so early. ACT, a small biotechnology company in Massachusetts, was the first to accomplish the cloning of human cells for therapeutic use. Dr. Michael West, the company's chief executive officer, emphatically stated that his company's objective was research in cloning for exclusively therapeutic treatments and not for reproductive or human cloning purposes. Nevertheless, the public had a strong reaction to this news.

Those who favor the use of embryonic stem cells tend to see the potential to cure genetic problems, and they emphasize the hope of a cure and improved lives for patients with fatal genetic diseases. Opponents recognize that human life begins at conception, and they believe that the price of a cure should not result in the taking of another life, as harvesting embryonic stem cells for this research results in the destruction of embryos. Therefore, embryonic stem cells can be seen as a matter of life by those who can benefit from this technology, or as a matter of death by those who do not agree with the sacrifice of embryos for the production of stem cells.

This is not an easy debate. Imagine a case in which the only hope of cure for a young mother with two small children is the use of embryonic stem cell therapy. Even if this mother's dramatic situation might suggest that it would be ethical to sacrifice a mass of frozen cells stored in liquid nitrogen to obtain the needed stem cells for the therapy, the point that deserves to be addressed is this: Who would have the right to sacrifice a defenseless life (embryo) to save another (adult individual)?

The use of stem cells from bone marrow, umbilical cord, and other parts of the adult human body has not generated as much controversy. The potential benefits from stem cell therapy have been widely discussed. However, the use of embryonic stem cells has raised heated debates in public and scientific arenas. These cells are usually harvested from spare embryos generated through in vitro fertilization that have not been implanted in prospective mothers. Even if the scientist that uses stem cells were not responsible for producing them, he or she would be aiding in this process by creating a demand that results in the destruction of embryos, being an accomplice in the process. This is the same rationale used by the governments that burn ivory confiscated from smugglers, as well as the refusal of the scientific community to use the knowledge generated by the Nazis in the horrific human experiments conducted at the concentration camps during World War II.

This and many other recent discoveries in biotechnology have been occupying the world media. Although the scientific bases for cloning are easy to understand, the greater challenge for society is to address its ethical issues.

The lack of ethical references and the speed of development of new knowledge have exposed the society's lack of readiness to address current ethical issues. Sometimes society fears a technology with great potential benefits; other times it is apathetic about technology with proven negative impacts. Individualism and relativist morale, ideals in fashion in this postmodern society, are fertile ground for justifiable mistakes. These ideologies emphasize that nobody should deny anything to himself or herself that is good unless it is especially harmful to his or her neighbor. The ethical boundaries of society reflect the moral principles that it possesses. Society is dynamic and so are its ethical values. This doesn't mean, however, that the principles within society should develop in a liberal way.

Humans were created with intelligence and this allows them to develop new technologies and expand science. Along with this intelligence they have the freedom to choose between good and bad.

Why should one not be in favor of the evolution of the human race? What are the limits of what is morally acceptable? Any answer that deserves consideration should address the dilemmas of society in light of its principles, morals, and religious beliefs. These are some of the challenges society must deal with.

Tags: Bio Technology, Bio Genetics, Cloning

Problems encountered during Cloning

0 comments
There are two major problems or limitations found in the cloning of mammals. First, following the introduction of the donor's nucleus into the egg, it must be reimplanted into a gestating surrogate mother. Most of the implanted eggs abort, forcing scientists to perform several implantations, in the hopes that at least one of the females will have normal gestation. In the case of amphibians (e.g., toads), the development of the embryo occurs outside of the adult's body, thereby facilitating the development of the fetus.

The second major challenge in animal cloning is the size of the fetus at birth. Most of the surrogate mothers have to deliver via Cesarean section. This is especially true in bovines, as the clones tend to be about twice as big as normal newborn calves. The large size of the fetus during gestation can represent a substantial risk for the surrogate mother. Additionally, clones tend to have a high incidence of birth defects, and many clones die in the first hours following birth. Common abnormalities observed in cloned animals include failures of the kidney, heart, circulatory system, liver, and lungs. In addition, the placenta of the surrogate mother does not always function properly during gestation.

The causes of the high abortion rate and abnormalities in clones are still not completely understood, but it is suspected that they are at least partially the result of the complexity of the genetic reprogramming that takes place in the genes from the donor that are inserted into the egg. If a gene is expressed inadequately or it is not expressed at a critical point in development, the result can be a developmental defect. Genetic reprogramming involves the regulation of thousands of genes in a systematic and orderly way. Any asynchrony in the expression of the genes can contribute to defects in the fetus or even result in abortion. Additionally, when cloning is done with nuclei from somatic cells, they bear any preexisting mutations that might have occurred after the cells had differentiated into specialized cells. These mutations would have otherwise been screened out in gametogenesis.

With the current knowledge and technology, mammalian cloning is still a highly unsafe and inefficient procedure. The expectation is that, as new knowledge is generated from more experience, the main limitations in cloning will be at least partially solved. This science is continuing to make progress worldwide, even in developing counties. For example, in Brazil, Embrapa-Cenargen recently pioneered the cloning of the first bovine calf from somatic cells, born in March 2001.

Tags: Bio Technology, Bio Genetics, Cloning

Understanding of Basics of Cloning

2 comments
A clone can be defined as an individual or group of individuals that descend, through asexual reproduction, from a single individual. In other words, a clone is an exact copy of the original individual. Humans have practiced cloning of plant species for thousands of years. A leaf, a piece of stem, or root of a certain plant placed in a pot with soil or in a petri dish with tissue culture media can regenerate a new individual, genetically identical (clone) to the plant from which the leaf, stem, or root piece was taken. Today, cloning is a common agricultural practice used in many species that can easily reproduce asexually, such as sugar cane, banana, citrus, potato, strawberry, many grasses, roses, and many tree crops.

Cloning is based on two principles:
1) All cells of any organism contain the complete genetic makeup of the species.
2) Totipotence, the ability of one cell to differentiate and regenerate a completely new individual

Although the regeneration of a complete plant from a somatic tissue (leaf, root, stem, etc.) is an ancient practice, it was only in the 1950s that biologists discovered the principles behind regeneration of whole individuals from a single cell. Unlike animal cells, most plant cells retain their potential to express any of their genes and therefore are able to repeat the developmental processes involved in regenerating complete individuals. Cloning of plants offers the possibility of developing millions of individuals exactly identical to the original source of the regenerated cells. This is a common method of reproduction in asexual plant species.

Most animal cells do not have that same capability of naturally regenerating a complete individual from a cell. In animals, this potential is lost during cell specialization. A specific class of cells called stem cells is the only cell type known to retain their totipotence. Stem cells can be found in marrow tissue, fat tissue, and developing embryos. These types of cells have been the focus of animal cloning efforts. In animals, cloning can be accomplished using the technique called nuclear transplant. The technique has been used for many years in animal cloning using embryonic cells for amphibians such as toads. Animal embryonic cells maintain their totipotence after the first few cellular divisions. As the embryo continues its development, the cells lose their ability to differentiate into other cells and, consequently, the capability for complete regeneration ceases quickly. Contrary to the relative ease of nuclear cell transfer in amphibians, this process is much more complex in mammals. Although cloning of toads was accomplished for the first time in 1952, cloning of mice using the same technique was not accomplished until 1977.

Cloning using nuclear transfer involves the manipulation of two cells. The recipient cell is usually a nonfertilized egg from a female taken soon after ovulation. Harvesting of these eggs is done by laparoscopy or by transvaginal suction. The donor cell, which is the one providing the genetic material for regenerating the clone, is collected from the individual to be copied. Any somatic cell could be used for the purpose, including cells from the skin, mammary glands, or mucous membranes. Under a microscope, the recipient cell (egg) is held, by suction, at the end of a pipette. With an extremely fine micropipette, the chromosomes are removed. At this point the nucleus from the donor cell is then fused with the recipient egg previously deprived of its chromosomes. Some of the cells, if implanted into the uterus of a surrogate mother, start developing into an embryo and eventually a fetus. The procedure involves the removal or destruction of the chromosomes from the recipient egg cell, and the subsequent introduction of the chromosomes from the donor cell. The egg, with the newly introduced genetic material, begins the developmental process in the uterus of a surrogate mother to form a complete individual, genetically identical to the donor that supplied the nucleus. This technique has been used with success for cloning sheep, cattle, mice, monkeys, and other mammals.


The first cloned mammal from somatic cells of an adult donor was the sheep Dolly, born in February 1997. Dolly was cloned using mammary cells from an adult sheep. This widely covered event occurred at the Roslin Institute in Scotland, and the lead scientist was Dr. Ian Wilmut.

Tags: Bio Technology, Bio Genetics, Cloning

Why Human Cloning is Undesirable?

0 comments
There is a series of scientific reasons for not cloning human beings. Although many scientists and most of the public share this point of view, it is feared that personal ambition of unscrupulous scientists would make them blind to the scientific reasons for not cloning man. The success in animal cloning is evidence that this technology might be ready to justify its application to humans. In 2000, Dr. Panayiotis Zavos, an Israeli specialist in in vitro fertilization, and Dr. Severino Antinori, an Italian specialist in reproductive physiology, announced their intention to clone humans. In April 2002, Antinori claimed that he had two women carrying cloned babies.

After the birth of Dolly and the successful cloning of mice, cattle, monkeys, goats, and pigs, it is evident that cloning is not a completely safe procedure. Cloning of mammals is considered highly inefficient, and this is unlikely to change in the foreseeable future. Many cloning experiments have resulted in developmental flaws either during gestation or in the neonatal period. Even in the best cases, only a small percentage of cloned embryos survive to birth and, of those, many die shortly after birth. There is no reason to believe this would be any different with humans. This means that to achieve the successful generation of a human clone, many others will have been sacrificed in the developmental phases.

The few animal clones that have survived and been born show abnormal size, a phenomenon called increased offspring syndrome. It is believed that incorrect functioning of the placenta is one of the main causes of embryonic death. The suspected causes of newborn death are respiratory and circulatory problems. Some seemingly healthy survivors might possess immune system dysfunction or kidney and brain malformation. Those problems have been detected in practically all species in which cloning has been accomplished. Therefore, if an attempt to clone a human is made, the concern is not just with the embryos, but also with those that will live to be abnormal children and adults.

The abnormalities in the fetuses and in those few clones that are born alive cannot be easily traced to the nucleus of the donor. The most probable explanations are flaws in the genetic reprogramming or timing and expression of the correct developmental genes. Normal development depends on a necessary sequence of changes in the configuration of DNA and proteins coded by developmental genes. Those developmental changes control the specific genetic expression in the specialized tissues.

Genetic reprogramming of the entire genome is a natural process that happens during spermatogenesis and oogenesis, which can span over months and years in humans. During cloning, reprogramming of the donor's DNA must be done within minutes or, at the most, in a few short hours, during the period of time that nuclear transfer is completed and cell division begins to form the zygote.

Prenatal mortality in clones can occur due to inadequate reprogramming that results in improper gene expression. Some surviving clones have subtle genetic defects that, over time, result in life-threatening conditions. There is no information on genetic regulation in clones, but some evidence seems to indicate errors in gene expression in cloned animals. The expression of marked genes is significantly altered when embryos are cultivated in vitro before they are implanted in the uterus, indicating that even a minimal disturbance of the embryo's environment can have profound effects on gene regulation during development.

All the current evidence now suggests that the experiments on human cloning announced by Zavos and Antinori will have the same failure rates and occurrences of abnormalities that have been detected in animal cloning. Zavos tried to calm the public, informing them their research would use genetically perfect embryos to be implanted as a quality control. However, the public perception of reproductive biotechnology will be seriously damaged if the research fails and defective babies are born from human cloning experimentation. This would likely negatively affect other areas of research, such as the advancements being made with stem cells.

The National Bioethical Advisory Commission in the United States reached the following conclusion six years ago: "At the present, the use of cloning to generate a child would be a premature experiment, and would expose the fetus and the child in development to unacceptable risks." All the data gathered since seems to reinforce this point of view. In many countries, it is unlawful to perform research with human reproductive cells, thereby forbidding embryonic cloning.

Tags: Bio Technology, Bio Genetics, Cloning

Tuesday, June 16, 2009

Is Human Cloning Possible?

0 comments
After the cloning experience of Dolly the sheep, human cloning is theoretically and technically possible. The procedure would consist of taking an egg, removing its chromosomes, and then fusing it with a somatic cell from the individual to be cloned. Some believe that it is inevitable that some scientist will try to clone humans, if it is not already occurring. There seems to be a consensus that within a few years the news of the birth of the first human clone will be the major headline in the media. Scientists in South Korea reported success in creating a cloned human embryo, but it was destroyed instead of being implanted in a surrogate mother. Even if the first human clone is decades from birth, the idea that scientists are secretly trying to do it is a real possibility.

Scientists with an economic interest in this science have been expressing their viewpoint that it would be ethically acceptable to clone human beings. They argue that an embryo up to 10 days after fertilization cannot be considered a life because development of the brain begins at about 14 days after fertilization. It would be interesting to know how those scientists define the ethical limits in relation to their objectives.

It has been assumed by some that human cloning serves only the interests of the narcissists or neo-Nazis, those who would like to create the perfect race. In fact, several scenarios have been created that justify cloning of the Homo sapiens "animal." Some of those scenarios can seem extremely appealing, but an ethical analysis of the dilemmas that clones, their relatives, and society would face during their life indicates that cloning of the most intelligent and rational of the animals is not politically, socially, or religiously acceptable.

Some of the following scenarios show the complexity of the subject:

1) Consider the situation of a homosexual man who feels frustrated with his incapacity to bear children and wants to be cloned.

2) Consider the couple that wants to have a baby, but the husband is sterile. Assuming that cloning is an alternative, the couple could decide to clone the husband, and the wife could contribute as a surrogate mother. Would the child's responses to education differ though he is genetically identical to his father? Would he have the same tastes and preferences as the husband? What if a divorce occurs? How would the mother see her son, who is a copy of the man from whom she is divorced? Would the father have the right to custody of the child because he is genetically related to his father?

3) In another scenario, where a woman gives birth to her own clone, would she be her child's mother or twin sister with a different age?

Obviously, society changes over time. In vitro fertilization was illegal in many countries until about 20 years ago, and the idea of heart transplants was considered immoral in the past. Public opinion on human cloning will probably change in the next few years, but cloning will likely be banned globally before the birth of the first human clone. It would be a terrible mistake to wait until the birth of a baby with genetic defects before that decision is reached. Current experience with animals shows that this technology has too many technical and ethical problems to justify experimentation in humans.

Ethicists are concerned that clones would be considered inferior to human beings, and they would be subject to the limitations and expectations of the knowledge of the copied person. These expectations could be false, as both genetic factors and the environment determine personality. For example, a clone of an extroverted person could be more introverted, depending on his or her upbringing. Clones of athletes, artists, scientists, and politicians could choose different professional careers based on opportunities and the environment in which they are raised.

Predicting the future of human cloning is not an easy task. History shows that society is dynamic, that ethical values change, and moral principles distort over time. In other words, only time will tell. The challenge for bioethicists is to keep science progressing while maintaining the sanctity of life. It is a mistake to think that genetically identical means identical individuals. In the 1978 movie The Boys of Brazil, based on Ira Levin's bestseller, a scientist conspires after World War II to clone Hitler, with the objective of raising a new generation of Nazi leaders. The film shows that without intense indoctrination, the clones can be influenced to pursue other activities than becoming dictators.

Tags: Bio Technology, Bio Genetics, Cloning

Thursday, May 21, 2009

What is Transgenic Locus

0 comments
Gene constructs used in genetic transformation posses a promoter, coding region, and termination sequence. In the vicillin promoter, specific for expression in seeds, drives the expression of the gene UDP 6-glucose dehydrogenase in the antisense orientation. The construct also possesses the NOS (noplaine synthase) termination sequence, which marks the site for the end of transcription. Besides the transgene of interest, in general, reporter genes are introduced simultaneously to facilitate the identification and selection of transformed individuals.

For the selection of the transformed cells, the gene construct contains a gene sequence that codes for antibiotic or herbicide resistance. Frequently, neomycin or hygromycin antibiotic resistance genes or the phosphinotricim acetyl transferase herbicide tolerance gene is included under a strong constitutive promoter, such as 35SCaMV. The transformed cells would be the only ones possessing the capability to grow in a medium with a selective agent (antibiotic or herbicide), thereby facilitating their selection.

Frequently, a gene reporter is also included in the genetic construction. The function of this reporter is to allow the visual identification of transformed cells. Three genes have been used as reporters in plant transformation: Glucaronidase (GUS), Luciferase (LUC) and Green Fluorescent Protein (GFP). GUS allows the identification of transformed individuals by the expression of a blue color, because they become blue in the presence of the chemicals X-Gal and IPTG (isopropyl beta D-thiogalactoside). Luciferase, a protein in fireflies, turns the transformed individuals phosphorescent, and GFP, isolated from a species of jellyfish, codes for a fluorescent-green color in transformed individuals.

Genetic transformation of individuals is a difficult task. The science behind the methods is understandable on a basic level, but the results from the procedures do not always work out as planned. Specific gene sequences are needed to induce the expression of a transgene, and genes are needed to identify the transformed cells. Still, the use of transformation is being improved to more accurately express desired traits in different organisms. The comprehension of the intricacies of transformation is a key to understanding the broad applications of biotechnology.


Tags: Bio Technology, Bio Genetics, Genetic Transformation

Know the Gene Expression

0 comments
All cells possess the typical number of chromosomes of their species. Therefore, root, epidermis, or pod cells of a soybean plant possess all 40 chromosomes typical of this species. However, not all of the genes are expressed in every cell. For instance, genes that code for chlorophyll production are expressed in the leaves and any other green part of the plant. However they are silenced in the roots, which is the reason these cells do not contain chlorophyll. Gene regulation is a complex process that is affected by a series of factors. A common occurrence in genetic engineering is a lack of expression after a gene has been transformed into an organism. Therefore, an understanding of mechanisms involved with gene expression is critical in genetic transformation.

In bacteria, some genes are activated while others are silenced, depending on the conditions in which these microorganisms are grown. For example, the bacteria Escherichia coli can use two different carbohydrates, lactose and glucose, as energy sources. The bacteria needs to synthesize specific enzymes that catalyze the breakdown of the carbohydrates into energy. The enzymes, like all other proteins, are coded by genes. When E. coli is cultivated in a medium with both glucose and lactose (preferably glucose), it metabolizes. The genes coding for the production of the enzymes that metabolize glucose are thus expressed preferentially. The metabolism of lactose requires an additional enzyme that is only synthesized, or activated, after the medium runs out of glucose and lactose is the only energy source available. This phenomenon is called gene regulation.

Gene expression in more complex organisms is still not completely understood. The complexity of gene regulation is a puzzle in the zygote, a cell formed by the union of sperm and egg cells, in which the genes coding for differing functions have to be activated in a precise and orderly manner. The same genetic information present in the zygote is also present in any other cell in the body, from muscles to skin. Obviously, different genes are activated or expressed in each organ in a different way.

Gene expression is not just a function of where the cell is, but also the result of environmental stimuli. Cells of a floral bud of soybeans differentiate into flowers when the plant is grown during long nights. If the soybean plant is grown during short nights, it continues vegetative growth and does not bloom. Another example of gene regulation occurs with animals, including humans. Testicle and ovary cells do not start the production of sexual hormones until the individual reaches puberty.

Another example of the complexity and importance of gene regulation can be observed in the metamorphosis and development of butterflies and moths. These insects take three forms during their lives: caterpillar, pupa, and adult butterfly or moth. The insect possesses the same genes and DNA during these three different developmental phases. Although the caterpillar, pupa, and adult have the same genes, it is interesting to observe that different genes are expressed in the three developmental phases. In the caterpillar phase, the genes for production of several legs and a stronger mouth capable of chewing leaves are expressed, but not the genes for production of wings. However, the genes for the formation of a delicate mouth apparatus, appropriate for nectar feeding, and genes for the formation of wings are active in the insect's adult phase. The gene expression pattern changes during insect development to allow for the correct progression of its life cycle.

The mechanisms regulating gene expression involve regulatory genes. As opposed to the genes discussed up to this point, these DNA sequences do not code for any protein. Their function is to promote the activation or the silencing of genes.

An important part of gene regulation is the promoters. A promoter is a DNA sequence preceding the gene, which contains regulatory sequences to control the rate of RNA transcription. Promoters control when and in which cells a certain gene is expressed. Through the manipulation of promoters it is possible to induce superexpression, underexpression, or even gene silencing.

Some promoters are constitutive—that is, they induce gene expression continually—whereas others are inducible. Among these, there are some that are chemically inducible, and others are activated by heat, light, or hormones. Some promoters are active in certain tissues and organs, but not in others. In this case, they are considered tissue-specific promoters, as in the case of chlorophyll production. The promoters of the chlorophyll genes are not active in roots, but they are active in the leaves and in all green parts of plants.
Some of the promoters frequently used in genetic engineering of plants include the following:
1) Constitutive
a) UBI from corn
b) 35SCaMV from a cauliflower virus

2) Tissue-specific
a) Phaseolina promoter, a seed-specific promoter from field beans
b) Vicillin promoter, a seed-specific promoter from peas
c) Glutamine promoter, an endosperm-specific promoter from wheat

3) Inducible
a) Rubisco 5S promoter, inducible by light

Aside from promoters, other genetic factors are important in proper gene expression. Although the genetic code is universal, it is also considered degenerate, as more than a single codon codes for a certain amino acid. Different organisms have acquired the preferential use of specific codons for certain amino acids during evolution; this can also have an impact in gene expression. That was the case of the Bt gene from Bacillus thuringiensis introduced in corn. Initially, the expression of that bacterial gene in corn was low; however, when a transgene was reengineered to favor the preferential use of certain codons by corn, gene expression occurred at normal levels.

Several other factors can affect the expression of transgenes, such as the presence of a peptide signal, the site of its integration in the genome, the number of copies integrated, and transgene rearrangements during the integration process. Integration of transgenes in the host genome, in general, happens at random; that is, it can occur in any chromosome of the cell and it can land in any part of the chromosome. However, most of the transgenic varieties have the transgene inserted close to the ends of the chromosome. Multiple copies of the transgene are typically introgressed together.

Tags: Bio Technology, Bio Genetics, Genetic Transformation

Problems in Genetic Transformation

0 comments
Tissue culture has been identified as one of the largest obstacles in the development of transgenic plant products. It is necessary to develop protocols that allow the regeneration of whole individuals from the transformed cells or tissue. One of the difficulties faced by scientists is that regeneration methodologies work well with some, but not all species or germplasm within a species. This severely limits the spectrum of individuals that can be transformed. In many cases, the procedure has been the transfer of the transgene through classical genetics and breeding methods. An example of this is in the genetic transformation of wheat. Genetic transformation of most wheat varieties is very difficult because of problems in tissue culture. One variety, Bobwhite, is the exception, and protocols have been developed for the transformation of this wheat variety. Once a gene has been successfully transferred into Bobwhite, it can be moved into other varieties through traditional breeding methods.

Another difficulty associated with the use of tissue culture in transformation is somaclonal variations. Plants produced from tissue culture have higher mutation rates and the appearance of abnormal variation. This is due to the delicate environment in which cells are cultured. Many times, the cultured plants have problems associated with the cell cultures and not from the transgene integration.

Transformation methods currently in development promise to revolutionize the introduction of genes in plants. Some of these methods are already being used with the model plant Arabidopsis thaliana, commonly known as mouse ear cress. One of the methods involves the submersion of floral buds in a solution containing plasmids bearing the transgenes. Another alternative technique, still in development, is the transformation of seeds mediated by Agrobacterium tumefaciens. Although the methods have been used with success in Arabidopsis, the literature does not report its use in crop species. The key aspect of these two methods is that transformation is carried out without the need to regenerate plants through tissue culture. These methods are exciting because the transformation procedure works on the seeds that can then be planted to identify transgenic individuals.

Tags: Bio Technology, Bio Genetics, Genetic Transformation

Methods of Genetic Transformation

0 comments
Among the several methods of plant transformation, four have yielded the best results: Agrobacterium species-mediated transformation, microprojectile bombardment, microinjection, and direct transformation. Each of these methods has merits and limitations and is used in specific situations. At this time there is no single technique that is suitable for all species.

Agrobacterium Mediated Transformation
Tumors and uncontrolled cellular growth in plants can occur due to genetic factors or bacterial and viral infections. An example is crown gall in plants, where tumors are caused by bacteria that causes uncontrolled growth on the stem of the infected plants. This problem is caused by Agrobacterium tumefaciens, a soil bacterium that infects some plants because of a wound on the plant. Plasmids present in the bacteria are responsible for tumor growth after infection by A. tumefaciens. The bacteria are able to recognize wounds on the plant, and this induces the transfer of the bacterial plasmid into the plant. The plasmids are capable of integrating into the DNA of the host plant, causing uncontrolled plant growth and the formation of tumors. The ability of A. tumefaciens to efficiently transfer plasmid DNA into the host has made it important in early studies in genetic transformation.

Agrobacterium tumefaciens was the first vector used for introduction of foreign DNA in plant cells. Although Agrobacterium has only been used to infect dicot plant species, such as soybean, tomato, pea, and cotton, the protocol has been modified to allow the bacteria to infect some monocot (grass) species as well. Many research groups working with plants have found this to be the preferred transformation approach. Another soil bacteria, Agrobacterium rhizogenes, causes the growth of secondary roots after infection. This bacterial species has also been used for plant transformation.

The basis of this transformation method is the bacterial plasmid, which contains the genetic sequence that is integrated into the host genome. One of the most important parts of a plasmid is the region responsible for the translocation of its DNA into the host plant genome. This is called transfer DNA (T-DNA), and this area of DNA is key to the tumor growth in infected plants. The region is located between the right border and left border (RB and LB) of the plasmid. Plasmids also contain other important DNA sequences; some of them control the production of auxin and cytokinin, two important plant hormones involved in tumor formation. With the use of the restriction enzymes, a transgene can be introduced between the right border and left border of the plasmid, allowing the bacteria to transfer novel genes into the recipient plant.

One of the techniques used for transformation mediated by A. tumefaciens uses leaf disks. Leaf disks of about 6 mm in diameter are cultured on a tissue-culture media containing A. tumefaciens with plasmids containing the transgene. After approximately a month of incubation in the tissue culture medium, seedlings start to develop on the leaf disks. Through selection methods, transgenic seedlings are identified for whole plant regeneration.

Microparticle Bombardment
This technique has also been called microprojectile acceleration or biolistics, but microparticle bombardment is the formal name for the machine called a gene gun. This method, developed at Cornell University, was designated biolistic (biologic + ballistics = biolistic), because high-speed microscopic projectiles (microprojectiles) are accelerated into the cells to be transformed.
This transformation method consists of the acceleration of a macroprojectile loaded with millions of tungsten or gold microspheres about 1 ┬Ám in diameter (microparticle). The microspheres are coated with the transgene, or DNA of the gene of interest. Microspheres have a high specific mass, allowing them to acquire the needed momentum to penetrate the target cells. The macroparticle is propelled in the direction of the cells at high speed, but it is retained, after a small distance, on a steel mesh so that the microparticles continue in the direction of the target cells. Helium gas at high pressure is used to propel the macroparticle, and the acceleration chamber operates under a partial vacuum, which allows for improved microsphere movement. Once inside the target cells, the DNA coating the microspheres is released and can be integrated into the plant's genome.

Many of the commercial transgenic crop varieties on the market today were developed using the gene gun. However, due to its cost and the complex integration patterns resulting from this method, several research groups are reducing its use.

Microinjection
This method was developed for animal transformation but has also been extended to plants. Although very difficult and laborious, DNA microinjection has yielded positive results and has been used in several laboratories.

In this technique, microcapillary needles are used to introduce DNA directly into cells. Each cell to be transformed must be manipulated individually. One of the advantages of this method is that the optimum amount of DNA can be injected into the target cells, which helps to ensure optimal integration. Positive results have already been obtained in several crop species such as corn, wheat, soybean, tobacco, and rice, and in animals like salmon, cattle, and swine.

Direct Transformation
Transformation using direct methods was accomplished soon after the first Agrobacterium-mediated transformation. These methods use protoplasts (cells after the removal of the cellular wall) as targets for transformation. This is a simple method that consists of adding great amounts of transgenic plasmids to a protoplast culture, which guarantees that a small proportion of the protoplasts will be taken up (assimilated) by the plasmids. The assimilation rate can be increased with the addition of polyethylene glycol (PEG) or the use of an electric discharge (electroporation). No barrier to direct transformation has been detected, indicating that this method can be used with virtually any species. The problem with this method lies in the difficulty of regenerating a whole plant starting from protoplasts. Therefore, it has not been used as widely as the other methods.

Tags: Bio Technology, Bio Genetics, Genetic Transformation

Understanding Genetic Transformation

0 comments
The term genetically modified is frequently used to describe organisms that were genetically transformed or engineered. The science of genetic engineering was developed with the objective of building genes for genetic transformation. Genetic transformation systems possess three main components:
1) A mechanism for introduction of the foreign DNA into the target cell.
2) A cell or tissue suitable for transformation.
3) A method for the identification and selection of transformed cells or individuals.

Success in transformation for any species depends on these three components. Obviously, each one must be optimized and, therefore, as technology develops, transformation should become a more routine activity. The final objective in transformation is the introduction of a new trait in an individual. When the desired trait exists in any other sexually compatible individual, the first alternative should be to transfer the trait through crossing and selection, as has been done in conventional breeding since the 19th century. Modern soybean, corn, cotton, and wheat varieties, as well as swine, cattle, and poultry lines used in agriculture to feed the world, were initially obtained by traditional methods of crossing and selection.

One of the main limitations of conventional genetic improvement is that the breeder is limited to traits among species that are sexually compatible. For instance, the field bean is a species rich in sulfur-containing amino acids. However, beans are naturally deficient in lysine. On the other hand, rice is naturally rich in lysine, but deficient in sulfur-containing amino acids. It is not possible to naturally cross these species, so the conventional plant breeder is unable to develop a new field bean variety with elevated lysine levels or a rice cultivar rich in sulfur-containing amino acids. Genetic transformation allows the exchange of genes between organisms previously limited by sexual incompatibility. With genetic engineering and transformation, it is possible to transfer genes among bacteria, animals, plants, and viruses. In fact, one of the areas of research in biotechnology is the improvement of nutritional profiles in crops. New, more nutritional bean and rice varieties can now be developed through advances in genetic engineering.The basic tools for genetic transformation are restriction enzymes, which are used to cut DNA at specific sites, and ligases, which catalyze the joining of DNA fragments. Using the right restriction enzymes, it is possible to cut the circular bacterial plasmid DNA, causing it to linearize. With a ligase, it is possible to add other DNA fragments containing the gene of interest and join them to the linearized plasmid. Under the right conditions, the ends of the plasmid, now with the added DNA fragments, rejoin to create a new circular plasmid with some DNA modifications. The new plasmid can be introduced into certain bacteria through a process called electroporation, and the bacteria can then be used to transfer the transgene to the target species. If the plasmid DNA is integrated into the genome of the recipient species and the transferred genes are expressed, the individual is considered to be transformed or transgenic.

Tags: Bio Technology, Bio Genetics, Genetic Transformation

Understanding Genetic Transformation

0 comments
The term genetically modified is frequently used to describe organisms that were genetically transformed or engineered. The science of genetic engineering was developed with the objective of building genes for genetic transformation. Genetic transformation systems possess three main components:

1) A mechanism for introduction of the foreign DNA into the target cell.

2) A cell or tissue suitable for transformation.

3) A method for the identification and selection of transformed cells or individuals.

Success in transformation for any species depends on these three components. Obviously, each one must be optimized and, therefore, as technology develops, transformation should become a more routine activity. The final objective in transformation is the introduction of a new trait in an individual. When the desired trait exists in any other sexually compatible individual, the first alternative should be to transfer the trait through crossing and selection, as has been done in conventional breeding since the 19th century. Modern soybean, corn, cotton, and wheat varieties, as well as swine, cattle, and poultry lines used in agriculture to feed the world, were initially obtained by traditional methods of crossing and selection.

One of the main limitations of conventional genetic improvement is that the breeder is limited to traits among species that are sexually compatible. For instance, the field bean is a species rich in sulfur-containing amino acids. However, beans are naturally deficient in lysine. On the other hand, rice is naturally rich in lysine, but deficient in sulfur-containing amino acids. It is not possible to naturally cross these species, so the conventional plant breeder is unable to develop a new field bean variety with elevated lysine levels or a rice cultivar rich in sulfur-containing amino acids. Genetic transformation allows the exchange of genes between organisms previously limited by sexual incompatibility. With genetic engineering and transformation, it is possible to transfer genes among bacteria, animals, plants, and viruses. In fact, one of the areas of research in biotechnology is the improvement of nutritional profiles in crops. New, more nutritional bean and rice varieties can now be developed through advances in genetic engineering.The basic tools for genetic transformation are restriction enzymes, which are used to cut DNA at specific sites, and ligases, which catalyze the joining of DNA fragments. Using the right restriction enzymes, it is possible to cut the circular bacterial plasmid DNA, causing it to linearize. With a ligase, it is possible to add other DNA fragments containing the gene of interest and join them to the linearized plasmid. Under the right conditions, the ends of the plasmid, now with the added DNA fragments, rejoin to create a new circular plasmid with some DNA modifications. The new plasmid can be introduced into certain bacteria through a process called electroporation, and the bacteria can then be used to transfer the transgene to the target species. If the plasmid DNA is integrated into the genome of the recipient species and the transferred genes are expressed, the individual is considered to be transformed or transgenic.

Tags: Bio Technology, Bio Genetics, Genetic Transformation

Friday, May 8, 2009

Understanding Stem Cell Gene Therapy

1 comments
Stem cell therapy or therapeutic cloning does not involve gene therapy itself. However, in the future it might be used in conjunction with gene therapy for regeneration of tissue and organs after they have been treated with corrective genes. Visually, stem cells are not distinguishable from any other cells of the human body. Under a common microscope (magnification 20 to 40 times), those cells can only be observed using special dyes. Visually there is no significant difference in such cells. The real differences exist at the DNA level, where gene expression is amendable to signals influencing protein expression. The cells can differentiate into any of the 220 cell types of the human body (e.g., kidneys, heart, liver, skin, or retina), a phenomenon called pluripotency. At birth, stem cells can be harvested from an individual's bone marrow, fat tissue, and the umbilical cord. Embryonic stem cells are harvested from embryos up to a few days after fertilization.

Another characteristic of stem cells is their capability to grow indefinitely. Whereas the remaining body cells have a biological programming that limits the number of cell divisions they can go through before dying, stem cells can be maintained indefinitely in a petri dish with nutritive media.

Stem cell therapy provides hope for a cure for patients of incurable afflictions such as Parkinson's disease and Alzheimer's disease, and also for people suffering from paralysis resulting from spinal cord injuries.

At first, some opponents speculated that stem cells would be used in nurseries to produce organs such as livers, hearts, and virtually any other body part. However, most organs possess complex structures with ducts and valves, making it impossible to produce them outside of the organism. Stem cells have opened a new avenue for disease treatment. For example, the injection of stem cells into the liver of a patient with cirrhosis or hepatitis could result in new tissue capable of performing its role. Stem cell therapy also has great potential to cure rheumatoid arthritis and some heart diseases. Recent research has found that spine-injured mice suffering from paralysis were able to move their legs following an injection of stem cells.

Some people believe that if human stem cells are as versatile as those of mice, they might be the long sought after fountain of youth. The combination of stem cells with gene therapy might allow rebuilding of new body parts to substitute for old and defective ones. Right now, different procedures are being tested for curing ADA deficiency. Somatic cell gene therapies have the limitation of lasting for only a few months, which in turn requires repeated applications. With the use of stem cells to regenerate healthy bone marrow cells, a permanent cure is expected, as healthy cells have the capability to grow and divide continuously.

Embryonic stem cells, from embryos about four days old, have been at the center of a heated debate due to ethical issues. The main disagreement is whether or not a four-day-old embryo is already a human life. When would an embryo or a fetus reach the status of life? Those that support the use of embryonic stem cells would argue that human life would not begin until about the 14th day after the fertilization, whereas the opposition argues that life begins at conception (i.e., at the moment of the fertilization of the egg by the sperm). For many, the destruction of embryos for the purpose of treating another human being is wrong. Recently, in the United States, the Bush administration broadened the definition of a child eligible for coverage under the Children's Health Insurance Program by classifying a developing fetus as an "unborn child." Many activists are arguing that the Bush administration's proposal demonstrates its commitment to the strategy of undermining a woman's right to choose abortion by ascribing legal rights to embryos.

Tags: Bio Technology, Bio Genetics, Gene Therapy