StemCell Therapy

Genetic Engineering

Genetic engineering, also known as recombinant DNA technology, means altering the genes in a living organism to produce a Genetically Modified Organism (GMO) with a new genotype. Various kinds of genetic modification are possible: inserting a foreign gene from one species into another, forming a transgenic organism; altering an existing gene so that its product is changed; or changing gene expression so that it is translated more often or not at all.

Genetic engineering is a very young discipline, and is only possible due to the development of techniques from the 1960s onwards. Watson and Crick have made these techniques possible from our greater understanding of DNA and how it functions following the discovery of its structure in 1953. Although the final goal of genetic engineering is usually the expression of a gene in a host, in fact most of the techniques and time in genetic engineering are spent isolating a gene and then cloning it. This table lists the techniques that we shall look at in detail.

1

cDNA

To make a DNA copy of mRNA

2

To cut DNA at specific points, making small fragments

3

DNA Ligase

To join DNA fragments together

4

Vectors

To carry DNA into cells and ensure replication

5

Plasmids

Common kind of vector

6

Gene Transfer

To deliver a gene to a living cells

7

Genetic Markers

To identify cells that have been transformed

8

To make exact copies of bacterial colonies on an agar plate

9

PCR

To amplify very small samples of DNA

10

DNA probes

To identify and label a piece of DNA containing a certain sequence

11

Shotgun *

To find a particular gene in a whole genome

12

Antisense genes *

To stop the expression of a gene in a cell

13

Gene Synthesis

To make a gene from scratch

14

Electrophoresis

To separate fragments of DNA

* Additional information that is not directly included in AS Biology. However it can help to consolidate other techniques.

Complementary DNA (cDNA) is DNA made from mRNA. This makes use of the enzyme reverse transcriptase, which does the reverse of transcription: it synthesises DNA from an RNA template. It is produced naturally by a group of viruses called the retroviruses (which include HIV), and it helps them to invade cells. In genetic engineering reverse transcriptase is used to make an artificial gene of cDNA as shown in this diagram.

Complementary DNA has helped to solve different problems in genetic engineering:

It makes genes much easier to find. There are some 70 000 genes in the human genome, and finding one gene out of this many is a very difficult (though not impossible) task. However a given cell only expresses a few genes, so only makes a few different kinds of mRNA molecule. For example the b cells of the pancreas make insulin, so make lots of mRNA molecules coding for insulin. This mRNA can be isolated from these cells and used to make cDNA of the insulin gene.

These are enzymes that cut DNA at specific sites. They are properly called restriction endonucleases because they cut the bonds in the middle of the polynucleotide chain. Some restriction enzymes cut straight across both chains, forming blunt ends, but most enzymes make a staggered cut in the two strands, forming sticky ends.

The cut ends are sticky because they have short stretches of single-stranded DNA with complementary sequences. These sticky ends will stick (or anneal) to another piece of DNA by complementary base pairing, but only if they have both been cut with the same restriction enzyme. Restriction enzymes are highly specific, and will only cut DNA at specific base sequences, 4-8 base pairs long, called recognition sequences.

Restriction enzymes are produced naturally by bacteria as a defence against viruses (they restrict viral growth), but they are enormously useful in genetic engineering for cutting DNA at precise places ("molecular scissors"). Short lengths of DNA cut out by restriction enzymes are called restriction fragments. There are thousands of different restriction enzymes known, with over a hundred different recognition sequences. Restriction enzymes are named after the bacteria species they came from, so EcoR1 is from E. coli strain R, and HindIII is from Haemophilis influenzae.

This enzyme repairs broken DNA by joining two nucleotides in a DNA strand. It is commonly used in genetic engineering to do the reverse of a restriction enzyme, i.e. to join together complementary restriction fragments.

The sticky ends allow two complementary restriction fragments to anneal, but only by weak hydrogen bonds, which can quite easily be broken, say by gentle heating. The backbone is still incomplete.

DNA ligase completes the DNA backbone by forming covalent bonds. Restriction enzymes and DNA ligase can therefore be used together to join lengths of DNA from different sources.

In biology a vector is something that carries things between species. For example the mosquito is a disease vector because it carries the malaria parasite into humans. In genetic engineering a vector is a length of DNA that carries the gene we want into a host cell. A vector is needed because a length of DNA containing a gene on its own wont actually do anything inside a host cell. Since it is not part of the cells normal genome it wont be replicated when the cell divides, it wont be expressed, and in fact it will probably be broken down pretty quickly. A vector gets round these problems by having these properties:

It is big enough to hold the gene we want (plus a few others), but not too big.

It is circular (or more accurately a closed loop), so that it is less likely to be broken down (particularly in prokaryotic cells where DNA is always circular).

It contains control sequences, such as a replication origin and a transcription promoter, so that the gene will be replicated, expressed, or incorporated into the cells normal genome.

It contain marker genes, so that cells containing the vector can be identified.

Many different vectors have been made for different purposes in genetic engineering by modifying naturally-occurring DNA molecules, and these are now available off the shelf. For example a cloning vector contains sequences that cause the gene to be copied (perhaps many times) inside a cell, but not expressed. An expression vector contains sequences causing the gene to be expressed inside a cell, preferably in response to an external stimulus, such as a particular chemical in the medium. Different kinds of vector are also available for different lengths of DNA insert:

Type of vector

Max length of DNA insert

10 kbp

Virus or phage

30 kbp

Bacterial Artificial Chromosome (BAC)

500 kbp

Plasmids are by far the most common kind of vector, so we shall look at how they are used in some detail. Plasmids are short circular bits of DNA found naturally in bacterial cells. A typical plasmid contains 3-5 genes and there are usually around 10 copies of a plasmid in a bacterial cell. Plasmids are copied separately from the main bacterial DNA when the cell divides, so the plasmid genes are passed on to all daughter cells. They are also used naturally for exchange of genes between bacterial cells (the nearest they get to sex), so bacterial cells will readily take up a plasmid. Because they are so small, they are easy to handle in a test tube, and foreign genes can quite easily be incorporated into them using restriction enzymes and DNA ligase.

One of the most common plasmids used is the R-plasmid (or pBR322). This plasmid contains a replication origin, several recognition sequences for different restriction enzymes (with names like PstI and EcoRI), and two marker genes, which confer resistance to different antibiotics (ampicillin and tetracycline).

The diagram below shows how DNA fragments can be incorporated into a plasmid using restriction and ligase enzymes. The restriction enzyme used here (PstI) cuts the plasmid in the middle of one of the markergenes (well see why this is useful later). The foreign DNA anneals with the plasmid and is joined covalently by DNA ligase to form a hybrid vector (in other words a mixture or hybrid of bacterial and foreign DNA). Several other products are also formed: some plasmids will simply re-anneal with themselves to re-form the original plasmid, and some DNA fragments will join together to form chains or circles. Theses different products cannot easily be separated, but it doesnt matter, as the marker genes can be used later to identify the correct hybrid vector.

Vectors containing the genes we want must be incorporated into living cells so that they can be replicated or expressed. The cells receiving the vector are called host cells, and once they have successfully incorporated the vector they are said to be transformed. Vectors are large molecules which do not readily cross cell membranes, so the membranes must be made permeable in some way. There are different ways of doing this depending on the type of host cell.

Heat Shock. Cells are incubated with the vector in a solution containing calcium ions at 0C. The temperature is then suddenly raised to about 40C. This heat shock causes some of the cells to take up the vector, though no one knows why. This works well for bacterial and animal cells.

Electroporation. Cells are subjected to a high-voltage pulse, which temporarily disrupts the membrane and allows the vector to enter the cell. This is the most efficient method of delivering genes to bacterial cells.

Viruses. The vector is first incorporated into a virus, which is then used to infect cells, carrying the foreign gene along with its own genetic material. Since viruses rely on getting their DNA into host cells for their survival they have evolved many successful methods, and so are an obvious choice for gene delivery. The virus must first be genetically engineered to make it safe, so that it cant reproduce itself or make toxins. Three viruses are commonly used:

1. Bacteriophages (or phages) are viruses that infect bacteria. They are a very effective way of delivering large genes into bacteria cells in culture.

2. Adenoviruses are human viruses that causes respiratory diseases including the common cold. Their genetic material is double-stranded DNA, and they are ideal for delivering genes to living patients in gene therapy. Their DNA is not incorporated into the hosts chromosomes, so it is not replicated, but their genes are expressed.

The adenovirus is genetically altered so that its coat proteins are not synthesised, so new virus particles cannot be assembled and the host cell is not killed.

3. Retroviruses are a group of human viruses that include HIV. They are enclosed in a lipid membrane and their genetic material is double-stranded RNA. On infection this RNA is copied to DNA and the DNA is incorporated into the hosts chromosome. This means that the foreign genes are replicated into every daughter cell.

After a certain time, the dormant DNA is switched on, and the genes are expressed in all the host cells.

Plant Tumours. This method has been used successfully to transform plant cells, which are perhaps the hardest to do. The gene is first inserted into the Ti plasmid of the soil bacterium Agrobacterium tumefaciens, and then plants are infected with the bacterium. The bacterium inserts the Ti plasmid into the plant cells' chromosomal DNA and causes a "crown gall" tumour. These tumour cells can be cultured in the laboratory and whole new plants grown from them by micropropagation. Every cell of these plants contains the foreign gene.

Gene Gun. This extraordinary technique fires microscopic gold particles coated with the foreign DNA at the cells using a compressed air gun. It is designed to overcome the problem of the strong cell wall in plant tissue, since the particles can penetrate the cell wall and the cell and nuclear membranes, and deliver the DNA to the nucleus, where it is sometimes expressed.

Micro-Injection. A cell is held on a pipette under a microscope and the foreign DNA is injected directly into the nucleus using an incredibly fine micro-pipette. This method is used where there are only a very few cells available, such as fertilised animal egg cells. In the rare successful cases the fertilised egg is implanted into the uterus of a surrogate mother and it will develop into a normal animal, with the DNA incorporated into the chromosomes of every cell.

Liposomes. Vectors can be encased in liposomes, which are small membrane vesicles (see module 1). The liposomes fuse with the cell membrane (and sometimes the nuclear membrane too), delivering the DNA into the cell. This works for many types of cell, but is particularly useful for delivering genes to cell in vivo (such as in gene therapy).

These are needed to identify cells that have successfully taken up a vector and so become transformed. With most of the techniques above less than 1% of the cells actually take up the vector, so a marker is needed to distinguish these cells from all the others. Well look at how to do this with bacterial host cells, as thats the most common technique.

A common marker, used in the R-plasmid, is a gene for resistance to an antibiotic such as tetracycline. Bacterial cells taking up this plasmid can make this gene product and so are resistant to this antibiotic. So if the cells are grown on a medium containing tetracycline all the normal untransformed cells, together with cells that have taken up DNA thats not in a plasmid (99%) will die. Only the 1% transformed cells will survive, and these can then be grown and cloned on another plate.

Replica plating is a simple technique for making an exact copy of an agar plate. A pad of sterile cloth the same size as the plate is pressed on the surface of an agar plate with bacteria growing on it. Some cells from each colony will stick to the cloth. If the cloth is then pressed onto a new agar plate, some cells will be deposited and colonies will grow in exactly the same positions on the new plate. This technique has a number of uses, but the most common use in genetic engineering is to help solve another problem in identifying transformed cells.

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Genetic Engineering - BiologyMad

Genetic Engineering, the process of extracting DNA (deoxyribonucleic acid, which makes up the genes of all living things) from one organism and combining it with the DNA of another organism, thus introducing new hereditary traits into the recipient organism. The nature and characteristics of every living creature is determined by the special combinations of genes carried by its cells. The slightest alteration in these combinations can bring about significant changes in an organism and also its progeny. The science of devising techniques of modifying or controlling genes and genetic combinations is referred to as genetic engineering. It was practiced in one form or another in the past by farmers and agriculturists trying to create economically viable species of plants and animals through various breeding techniques Genetic engineering, as a science, was developed in the mid-1970's primarily to create new strains of microorganisms that produce certain chemicals useful in manufacturing or as drugs. Genetic engineering is now also applied to improving plants and creating transgenic animals (animals containing foreign genetic material).

Some persons oppose genetic engineering on religious, ethical, or social grounds. Among the religious questions is whether humans have the right to transfer traits from one organism to another. A social concern is the possibility of creating harmful organisms that, if accidentally released into the environment, could cause epidemics.The creation of human clones, for example, is facing serious opposition especially on moral grounds. Organizations, such as the National Institutes of Health (NIH), are seeking to control the harmful effects of genetic engineering by imposing guidelines and safety measures for genetic experimentation. Treatment of hereditary defects through gene transplantation and controlled interchange of genes between specified species was approved in 1985 and 1987 respectively by the NIH and the National Academy of Sciences. The USDA has framed regulations for the genetic alteration of plants by plant breeders.

The U.S. Supreme Court ruled in 1980 that genetically engineered microorganisms could be patented. In 1988 the U.S. Patent and Trademark Office issued its first patent for a higher form of life, a transgenic mouse that is highly susceptible to certain cancers that appear frequently in humans. This mouse is used in cancer research.

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Genetic Engineering - HowStuffWorks

Genetic engineering is the process of removing a gene from one organism and putting it into another. Often, the removed genes are put into bacteria or yeast cells so that scientists can study the gene or the protein it produces more easily. Sometimes, genes are put into a plant or an animal.

One of the first genetic engineering advances involved the hormone insulin. Diabetes, a medical condition that affects millions of people, prevents the body from producing enough insulin necessary for cells to properly absorb sugar. Diabetics used to be treated with supplementary insulin isolated from pigs or cows. Although this insulin is very similar to human insulin, it is not identical. Bovine insulin is antigenic in humans. Antibodies produced against it would gradually destroy its efficacy.

Scientists got around the problem by putting the gene for human insulin into bacteria. The bacteria's cellular machinery, which is identical to the cellular machinery of all living things, "reads" the gene, and turns it into a protein-human insulin-through a process called translation.

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Interactives . DNA . Genetic Engineering

genetic engineering,the artificial manipulation, modification, and recombination of DNA or other nucleic acid molecules in order to modify an organism or population of organisms.

The term genetic engineering initially meant any of a wide range of techniques for the modification or manipulation of organisms through the processes of heredity and reproduction. As such, the term embraced both artificial selection and all the interventions of biomedical techniques, among them artificial insemination, in vitro fertilization (e.g., test-tube babies), sperm banks, cloning, and gene manipulation. But the term now denotes the narrower field of recombinant DNA technology, or gene cloning (see Figure), in which DNA molecules from two or more sources are combined either within cells or in vitro and are then inserted into host organisms in which they are able to propagate. Gene cloning is used to produce new genetic combinations that are of value to science, medicine, agriculture, or industry.

DNA is the carrier of genetic information; it achieves its effects by directing the synthesis of proteins. Most recombinant DNA technology involves the insertion of foreign genes into the plasmids of common laboratory strains of bacteria. Plasmids are small rings of DNA; they are not part of the bacteriums chromosome (the main repository of the organisms genetic information). Nonetheless, they are capable of directing protein synthesis, and, like chromosomal DNA, they are reproduced and passed on to the bacteriums progeny. Thus, by incorporating foreign DNA (for example, a mammalian gene) into a bacterium, researchers can obtain an almost limitless number of copies of the inserted gene. Furthermore, if the inserted gene is operative (i.e., if it directs protein synthesis), the modified bacterium will produce the protein specified by the foreign DNA.

A key step in the development of genetic engineering was the discovery of restriction enzymes in 1968 by the Swiss microbiologist Werner Arber. However, type II restriction enzymes, which are essential to genetic engineering for their ability to cleave a specific site within the DNA (as opposed to type I restriction enzymes, which cleave DNA at random sites), were not identified until 1969, when the American molecular biologist Hamilton O. Smith purified this enzyme. Drawing on Smiths work, the American molecular biologist Daniel Nathans helped advance the technique of DNA recombination in 197071 and demonstrated that type II enzymes could be useful in genetic studies. Genetic engineering itself was pioneered in 1973 by the American biochemists Stanley N. Cohen and Herbert W. Boyer, who were among the first to cut DNA into fragments, rejoin different fragments, and insert the new genes into E. coli bacteria, which then reproduced.

Genetic engineering has advanced the understanding of many theoretical and practical aspects of gene function and organization. Through recombinant DNA techniques, bacteria have been created that are capable of synthesizing human insulin, human growth hormone, alpha interferon, a hepatitis B vaccine, and other medically useful substances. Plants may be genetically adjusted to enable them to fix nitrogen, and genetic diseases can possibly be corrected by replacing bad genes with normal ones. Nevertheless, special concern has been focused on such achievements for fear that they might result in the introduction of unfavourable and possibly dangerous traits into microorganisms that were previously free of theme.g., resistance to antibiotics, production of toxins, or a tendency to cause disease.

The new microorganisms created by recombinant DNA research were deemed patentable in 1980, and in 1986 the U.S. Department of Agriculture approved the sale of the first living genetically altered organisma virus, used as a pseudorabies vaccine, from which a single gene had been cut. Since then several hundred patents have been awarded for genetically altered bacteria and plants.

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genetic engineering | Britannica.com

Genetic engineering (GE for short) is about scientists altering the 'recipes' for making life the genes which you find in all living things. Doing this is very clever and seems to be very useful. Back in the 1990s, many 'Greens' campaigned against genetic engineering and still do. They predicted disaster but that hasn't happened. Nobody has died from eating genetically modified (GM) food. They were also worried about the private GE companies' ownership of the recipes genes for making these new life forms. So is genetic engineering okay? My guide explains the basics but it's up to you to make up your own mind about GE.

Finding your way around my GE Guide You can jump to any part that interests you from the table below. If you want to start at the beginning, click the green arrow below (forward to 'Genes, snails and whales').

Table of contents

Genes, snails and whales What makes you human or me a penguin? What are genes?

Tried and tested Life on Earth has been around for a long time so it's been well tested.

Adapt or die Only the fittest life survives. Here's how it does it.

Coils and corkscrews About that incredible stuff DNA.

Copycat: How DNA copies itself.

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Genetic engineering: a guide for kids by Tiki the Penguin

Genetic engineering is the deliberate, controlled manipulation of the genes in an organism with the intent of making that organism better in some way. This is usually done independently of the natural reproductive process. The result is a so-called genetically modified organism (GMO). To date, most of the effort in genetic engineering has been focused on agriculture.

Proponents of genetic engineering claim that it has numerous benefits, including the production of food-bearing plants that are resistant to extreme weather and adverse climates, insect infestations, disease, molds, and fungi. In addition, it may be possible to reduce the amount of plowing necessary in the farming process, thereby saving energy and minimizing soil erosion. A major motivation is the hope of producing abundant food at low cost to reduce world hunger, both directly (by feeding GMOs to human beings) and indirectly (by feeding GMOs to livestock and fish, which can in turn be fed to humans).

Genetic engineering carries potential dangers, such as the creation of new allergens and toxins, the evolution of new weeds and other noxious vegetation, harm to wildlife, and the creation of environments favorable to the proliferation of molds and fungi (ironically, in light of the purported advantage in that respect). Some scientists have expressed concern that new disease organisms and increased antibiotic resistance could result from the use of GMOs in the food chain.

The darkest aspect of genetic engineering is the possibility that a government or institution might undertake to enhance human beings by means of genetic engineering. Some see the possibility of using this technology to create biological weapons.

Genetic engineering is also known as genetic modification.

This was last updated in May 2007

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What is genetic engineering? - Definition from WhatIs.com

Photo by: Gernot Krautberger

Genetic engineering is any process by which genetic material (the building blocks of heredity) is changed in such a way as to make possible the production of new substances or new functions. As an example, biologists have now learned how to transplant the gene that produces light in a firefly into tobacco plants. The function of that genethe production of lighthas been added to the normal list of functions of the tobacco plants.

Genetic engineering became possible only when scientists had discovered exactly what is a gene. Prior to the 1950s, the term gene was used to stand for a unit by which some genetic characteristic was transmitted from one generation to the next. Biologists talked about a "gene" for hair color, although they really had no idea as to what that gene was or what it looked like.

That situation changed dramatically in 1953. The English chemist Francis Crick (1916 ) and the American biologist James Watson (1928 ) determined a chemical explanation for a gene. Crick and Watson discovered the chemical structure for large, complex molecules that occur in the nuclei of all living cells, known as deoxyribonucleic acid (DNA).

DNA molecules, Crick and Watson announced, are very long chains or units made of a combination of a simple sugar and a phosphate group.

Amino acid: An organic compound from which proteins are made.

DNA (deoxyribonucleic acid): A large, complex chemical compound that makes up the core of a chromosome and whose segments consist of genes.

Gene: A segment of a DNA molecule that acts as a kind of code for the production of some specific protein. Genes carry instructions for the formation, functioning, and transmission of specific traits from one generation to another.

Gene splicing: The process by which genes are cut apart and put back together to provide them with some new function.

Genetic code: A set of nitrogen base combinations that act as a code for the production of certain amino acids.

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Genetic Engineering - humans, body, used, process, plants ...

The science of indirectly manipulating an organism's genes using techniques like molecular cloning and transformation to alter the structure and nature of genes is called genetic engineering. Genetic engineering can bring about a great amount of transformation in the characteristics of an organism by the manipulation of DNA, which is like the code inscribed in every cell determining how it functions. Like any other science, genetic engineering also has pros and cons. Let us look at some of them.

Pros of Genetic Engineering

Better Taste, Nutrition and Growth Rate Crops like potato, tomato, soybean and rice are currently being genetically engineered to obtain new strains with better nutritional qualities and increased yield. The genetically engineered crops are expected to have the capacity to grow on lands that are presently not suitable for cultivation. The manipulation of genes in crops is expected to improve their nutritional value as also their rate of growth. Biotechnology, the science of genetically engineering foods, can be used to impart a better taste to food.

Pest-resistant Crops and Longer Shelf life Engineered seeds are resistant to pests and can survive in relatively harsh climatic conditions. The plant gene At-DBF2, when inserted in tomato and tobacco cells is seen to increase their endurance to harsh soil and climatic conditions. Biotechnology can be used to slow down the process of food spoilage. It can thus result in fruits and vegetables that have a greater shelf life.

Genetic Modification to Produce New Foods Genetic engineering in food can be used to produce totally new substances such as proteins and other food nutrients. The genetic modification of foods can be used to increase their medicinal value, thus making homegrown edible vaccines available.

Modification of Genetic Traits in Humans Genetic engineering has the potential of succeeding in case of human beings too. This specialized branch of genetic engineering, which is known as human genetic engineering is the science of modifying genotypes of human beings before birth. The process can be used to manipulate certain traits in an individual.

Boost Positive Traits, Suppress Negative Ones Positive genetic engineering deals with enhancing the positive traits in an individual like increasing longevity or human capacity while negative genetic engineering deals with the suppression of negative traits in human beings like certain genetic diseases. Genetic engineering can be used to obtain a permanent cure for dreaded diseases.

Modification of Human DNA If the genes responsible for certain exceptional qualities in individuals can be discovered, these genes can be artificially introduced into genotypes of other human beings. Genetic engineering in human beings can be used to change the DNA of individuals to bring about desirable structural and functional changes in them.

Cons of Genetic Engineering

May Hamper Nutritional Value Genetic engineering in food involves the contamination of genes in crops. Genetically engineered crops may supersede natural weeds. They may prove to be harmful for natural plants. Undesirable genetic mutations can lead to allergies in crops. Some believe that genetic engineering in foodstuffs can hamper their nutritional value while enhancing their taste and appearance.

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Pros and Cons of Genetic Engineering - Buzzle

What is genetic engineering? Genetic engineering is the process of manually adding new DNA to an organism. The goal is to add one or more new traits that are not already found in that organism. Examples of genetically engineered (transgenic) organisms currently on the market include plants with resistance to some insects, plants that can tolerate herbicides, and crops with modified oil content.

Understanding Genetic Engineering: Basic Biology To understand how genetic engineering works, there are a few key biology concepts that must be understood.

Small segments of DNA are called genes. Each gene holds the instructions for how to produce a single protein. This can be compared to a recipe for making a food dish. A recipe is a set of instructions for making a single dish.

An organism may have thousands of genes. The set of all genes in an organism is called a genome. A genome can be compared to a cookbook of recipes that makes that organism what it is. Every cell of every living organism has a cookbook.

CONCEPT #2: Why are proteins important? Proteins do the work in cells. They can be part of structures (such as cell walls, organelles, etc). They can regulate reactions that take place in the cell. Or they can serve as enzymes, which speed-up reactions. Everything you see in an organism is either made of proteins or the result of a protein action.

How is genetic engineering done? Genetic engineering, also called transformation, works by physically removing a gene from one organism and inserting it into another, giving it the ability to express the trait encoded by that gene. It is like taking a single recipe out of a cookbook and placing it into another cookbook.

1) First, find an organism that naturally contains the desired trait.

2) The DNA is extracted from that organism. This is like taking out the entire cookbook.

3) The one desired gene (recipe) must be located and copied from thousands of genes that were extracted. This is called gene cloning.

4) The gene may be modified slightly to work in a more desirable way once inside the recipient organism.

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UNL's AgBiosafety for Educators

Genetic engineering is a set of technologies used to change the genetic makeup of cells, including thetransfer of genes within and across species boundaries to produce improved or novel organisms. The techniques involve sophisticated manipulations of genetic material and other biologically important chemicals.

Genes are the chemical blueprints that determine an organism's traits. Moving genes from one organism to another transfers those traits. Through genetic engineering, organisms can be given targeted combinations of new genesand therefore new combinations of traitsthat do not occur in nature and, indeed, cannot be developed by natural means. Such an approach is different from classical plant and animal breeding, which operates through selection across many generations for traits of interest. Classical breeding operates on traits, only indirectly selecting genes, whereas biotechnology targets genes, attempting to influence traits. The potential of biotechnology is to rapidly accelerate the rate of progress and efficiency of breeding.

Novel organisms

Nature can produce organisms with new gene combinations through sexual reproduction. A brown cow bred to a yellow cow may produce a calf of a completely new color. But reproductive mechanisms limit the number of new combinations. Cows must breed with other cows (or very near relatives). A breeder who wants a purple cow would be able to breed toward one only if the necessary purple genes were available somewhere in a cow or a near relative to cows. A genetic engineer has no such restriction. If purple genes are available anywhere in naturein a sea urchin or an iristhose genes could be used in attempts to produce purple cows. This unprecedented ability to shuffle genes means that genetic engineers can concoct gene combinations that would never be found in nature.

New risks

Genetic engineering is therefore qualitatively different from existing breeding technologies. It is a set of technologies for altering the traits of living organisms by inserting genetic material that has been manipulated to extract it from its source and successfully insert it in functioning order in target organisms. Because of this, genetic engineering may one day lead to the routine addition of novel genes that have been wholly synthesized in the laboratory.

In addition to desired benefits, novel organisms may bring novel risks as well. These risks must be carefully assessed to make sure that all effectsboth desired and unintendedare benign. UCS advocates caution, examination of alternatives, and careful, contextual, case-by-case evaluation of genetic enginering applications within an overall framework that moves agricultural systems of food production toward sustainability.

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What Is Genetic Engineering? | Union of Concerned Scientists

While scientific progress on molecular biology has a great potential to increase our understanding of nature and provide new medical tools, it should not be used as justification to turn the environment into a giant genetic experiment by commercial interests. The biodiversity and environmental integrity of the world's food supply is too important to our survival to be put at risk. What's wrong with genetic engineering (GE)?

Genetic engineering enables scientists to create plants, animals and micro-organisms by manipulating genes in a way that does not occur naturally.

These genetically modified organisms (GMOs) can spread through nature and interbreed with natural organisms, thereby contaminating non 'GE' environments and future generations in an unforeseeable and uncontrollable way.

Their release is 'genetic pollution' and is a major threat because GMOs cannot be recalled once released into the environment.

Because of commercial interests, the public is being denied the right to know about GE ingredients in the food chain, and therefore losing the right to avoid them despite the presence of labelling laws in certain countries.

Biological diversity must be protected and respected as the global heritage of humankind, and one of our world's fundamental keys to survival. Governments are attempting to address the threat of GE with international regulations such as the Biosafety Protocol.

April 2010: Farmers, environmentalists and consumers from all over Spain demonstrate in Madrid under the slogan "GMO-free agriculture." They demand the Government to follow the example of countries like France, Germany or Austria, and ban the cultivation of GM maize in Spain.

GMOs should not be released into the environment since there is not an adequate scientific understanding of their impact on the environment and human health.

We advocate immediate interim measures such as labelling of GE ingredients, and the segregation of genetically engineered crops and seeds from conventional ones.

We also oppose all patents on plants, animals and humans, as well as patents on their genes. Life is not an industrial commodity. When we force life forms and our world's food supply to conform to human economic models rather than their natural ones, we do so at our own peril.

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Genetic Engineering | Greenpeace International

During the latter stage stages of the 20th century, man harnessed the power of the atom, and not long after, soon realised the power of genes. Genetic engineering is going to become a very mainstream part of our lives sooner or later, because there are so many possibilities advantages (and disadvantages) involved. Here are just some of the advantages :

Of course there are two sides to the coin, here are some possible eventualities and disadvantages.

Genetic engineering may be one of the greatest breakthroughs in recent history alongside the discovery of the atom and space flight, however, with the above eventualities and facts above in hand, governments have produced legislation to control what sort of experiments are done involving genetic engineering. In the UK there are strict laws prohibiting any experiments involving the cloning of humans. However, over the years here are some of the experimental 'breakthroughs' made possible by genetic engineering.

Genetic engineering has been impossible until recent times due to the complex and microscopic nature of DNA and its component nucleotides. Through progressive studies, more and more in this area is being made possible, with the above examples only showing some of the potential that genetic engineering shows.

For us to understand chromosomes and DNA more clearly, they can be mapped for future reference. More simplistic organisms such as fruit fly (Drosophila) have been chromosome mapped due to their simplistic nature meaning they will require less genes to operate. At present, a task named the Human Genome Project is mapping the human genome, and should be completed in the next ten years.

The process of genetic engineering involves splicing an area of a chromosome, a gene, that controls a certain characteristic of the body. The enzyme endonuclease is used to split a DNA sequence and split the gene from the rest of the chromosome. For example, this gene may be programmed to produce an antiviral protein. This gene is removed and can be placed into another organism. For example, it can be placed into a bacteria, where it is sealed into the DNA chain using ligase. When the chromosome is once again sealed, the bacteria is now effectively re-programmed to replicate this new antiviral protein. The bacteria can continue to live a healthy life, though genetic engineering and human intervention has actively manipulated what the bacteria actually is. No doubt there are advantages and disadvantages, and this whole subject area will become more prominent over time.

The next page returns the more natural circumstances of genetic diversity.

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Genetic Engineering Advantages & Disadvantages - Biology ...

Gene therapy is the therapeutic delivery of nucleic acid polymers into a patient's cells as a drug to treat disease. The polymers are either expressed as proteins, interfere with protein expression, or possibly correct genetic mutations.

The most common form uses DNA that encodes a functional, therapeutic gene to replace a mutated gene. The polymer molecule is packaged within a "vector", which carries the molecule inside cells.

Gene therapy was conceptualized in 1972, by authors who urged caution before commencing human gene therapy studies. The first gene therapy experiment approved by the US Food and Drug Administration (FDA) occurred in 1990, when Ashanti DeSilva was treated for ADA-SCID.[1] By January 2014, some 2,000 clinical trials had been conducted or approved.[2]

Early clinical failures led to dismissals of gene therapy. Clinical successes since 2006 regained researchers' attention, although as of 2014, it was still largely an experimental technique.[3] These include treatment of retinal disease Leber's congenital amaurosis,[4][5][6][7]X-linked SCID,[8] ADA-SCID,[9][10]adrenoleukodystrophy,[11]chronic lymphocytic leukemia (CLL),[12]acute lymphocytic leukemia (ALL),[13]multiple myeloma,[14]haemophilia[10] and Parkinson's disease.[15] Between 2013 and April 2014, US companies invested over $600 million in the field.[16]

The first commercial gene therapy, Gendicine, was approved in China in 2003 for the treatment of certain cancers.[17] In 2012 Glybera, a treatment for a rare inherited disorder, became the treatment to be approved for clinical use in either Europe or the United States after its endorsement by the European Commission.[3][18]

Following early advances in genetic engineering of bacteria, cells and small animals, scientists started considering how to apply it to medicine. Two main approaches were considered replacing or disrupting defective genes.[19] Scientists focused on diseases caused by single-gene defects, such as cystic fibrosis, haemophilia, muscular dystrophy, thalassemia and sickle cell anemia. Glybera treats one such disease, caused by a defect in lipoprotein lipase.[18]

DNA must be administered, reach the damaged cells, enter the cell and express/disrupt a protein.[20] Multiple delivery techniques have been explored. The initial approach incorporated DNA into an engineered virus to deliver the DNA into a chromosome.[21][22]Naked DNA approaches have also been explored, especially in the context of vaccine development.[23]

Generally, efforts focused on administering a gene that causes a needed protein to be expressed. More recently, increased understanding of nuclease function has led to more direct DNA editing, using techniques such as zinc finger nucleases and CRISPR. The vector incorporates genes into chromosomes. The expressed nucleases then "edit" the chromosome. As of 2014 these approaches involve removing cells from patients, editing a chromosome and returning the transformed cells to patients.[24]

Other technologies employ antisense, small interfering RNA and other DNA. To the extent that these technologies do not alter DNA, but instead directly interact with molecules such as RNA, they are not considered "gene therapy" per se.[citation needed]

Gene therapy may be classified into two types:

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Written by Patrick Dixon

Futurist Keynote Speaker: Posts, Slides, Videos - Biotechnology, Genetics, Gene Therapy, Stem Cells

Genetic engineering is the alteration of genetic code by artificial means, and is therefore different from traditional selective breeding.

Genetic engineering examples include taking the gene that programs poison in the tail of a scorpion, and combining it with a cabbage. These genetically modified cabbages kill caterpillers because they have learned to grow scorpion poison (insecticide) in their sap.

Genetic engineering also includes insertion of human genes into sheep so that they secrete alpha-1 antitrypsin in their milk - a useful substance in treating some cases of lung disease.

Genetic engineering has created a chicken with four legs and no wings.

Genetic engineering has created a goat with spider genes that creates "silk" in its milk.

Genetic engineering works because there is one language of life: human genes work in bacteria, monkey genes work in mice and earthworms. Tree genes work in bananas and frog genes work in rice. There is no limit in theory to the potential of genetic engineering.

Genetic engineering has given us the power to alter the very basis of life on earth.

Genetic engineering has been said to be no different than ancient breeding methods but this is untrue. For a start, breeding or cross-breeding, or in-breeding (for example to make pedigree dogs) all work by using the same species. In contrast genetic engineering allows us to combine fish, mouse, human and insect genes in the same person or animal.

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Genetic Engineering : What is Genetic Engineering

Genetic engineering (GE) is the modification of an organisms genetic composition by artificial means, often involving the transfer of specific traits, or genes, from one organism into a plant or animal of an entirely different species. When gene transfer occurs, the resulting organism is called transgenic or a GMO (genetically modified organism).

Genetic engineering is different from traditional cross breeding, where genes can only be exchanged between closely related species. With genetic engineering, genes from completely different species can be inserted into one another. For example, scientists in Taiwan have successfully inserted jellyfish genes into pigs in order to make them glow in the dark.

All life is made up of one or more cells. Each cell contains a nucleus, and inside each nucleus are strings of molecules called DNA (deoxyribonucleic acid). Each strand of DNA is divided into small sections called genes. These genes contain a unique set of instructions that determine how the organism grows, develops, looks, and lives.

During genetic engineering processes, specific genes are removed from one organism and inserted into another plant or animal, thus transferring specific traits.

Nearly 400 million acres of farmland worldwide are now used to grow GE crops such as cotton, corn, soybeans and rice. In the United States, GE soybeans, corn and cotton make up 93%, 88% and 94% of the total acreage of the respective crops. The majority of genetically engineered crops grown today are engineered to be resistant to pesticides and/or herbicides so that they can withstand being sprayed with weed killer while the rest of the plants in the field die.

GE proponents claim genetically engineered crops use fewer pesticides than non-GE crops, when in reality GE plants can require even more chemicals. This is because weeds become resistant to pesticides, leading farmers to spray even more on their crops. This pollutes the environment, exposes food to higher levels of toxins, and creates greater safety concerns for farmers and farm workers.

Some GE crops are actually classified as pesticides. For instance, the New Leaf potato, which has since been taken off grocery shelves, was genetically engineered to produce the Bt (Bacillus thuringiensis) toxin in order to kill any pests that attempted to eat it. The actual potato was designated as a pesticide and was therefore regulated by the Environmental Protection Agency (EPA), instead of the Food & Drug Administration (FDA), which regulates food. Because of this, safety testing for these potatoes was not as rigorous as with food, since the EPA regulations had never anticipated that people would intentionally consume pesticides as food.

Adequate research has not yet been carried out to identify the effects of eating animals that have been fed genetically engineered grain, nor have sufficient studies been conducted on the effects of directly consuming genetically engineered crops like corn and soy. Yet despite our lack of knowledge, GE crops are widely used throughout the world as both human and animal food.

Scientists are currently working on ways to genetically engineer farm animals. Atlantic salmon have been engineered to grow to market size twice as fast as wild salmon, chickens have been engineered so that they cannot spread H5N1 avian flu to other birds, and research is being conducted to create cattle that cannot develop the infectious prions that can cause bovine spongiform encephalopathy (aka mad cow disease). At this point, no GE animals have been approved by the FDA to enter the food supply. Genetic engineering experiments on animals do, however, pose potential risks to food safety and the environment.

In 2003, scientists at the University of Illinois were conducting an experiment that involved inserting cow genes into female pigs in order to increase their milk production. They also inserted a synthetic gene to make milk digestion easier for the piglets. Although the experimental pigs were supposed to be destroyed, as instructed by the FDA, 386 offspring of the experimental pigs were sold to slaughterhouses, where they were processed and sent to grocery stores as pork chops, sausage, and bacon.

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Sustainable Table | Genetic Engineering

Genetic engineering, also called genetic modification, is the direct manipulation of an organism's genome using biotechnology. New DNA may be inserted in the host genome by first isolating and copying the genetic material of interest using molecular cloning methods to generate a DNA sequence, or by synthesizing the DNA, and then inserting this construct into the host organism. Genes may be removed, or "knocked out", using a nuclease. Gene targeting is a different technique that uses homologous recombination to change an endogenous gene, and can be used to delete a gene, remove exons, add a gene, or introduce point mutations.

An organism that is generated through genetic engineering is considered to be a genetically modified organism (GMO). The first GMOs were bacteria generated in 1973 and GM mice in 1974. Insulin-producing bacteria were commercialized in 1982 and genetically modified food has been sold since 1994. Glofish, the first GMO designed as a pet, was first sold in the United States December in 2003.[1]

Genetic engineering techniques have been applied in numerous fields including research, agriculture, industrial biotechnology, and medicine. Enzymes used in laundry detergent and medicines such as insulin and human growth hormone are now manufactured in GM cells, experimental GM cell lines and GM animals such as mice or zebrafish are being used for research purposes, and genetically modified crops have been commercialized.

IUPAC definition

Process of inserting new genetic information into existing cells in order to modify a specific organism for the purpose of changing its characteristics.

Note: Adapted from ref.[2][3]

Genetic engineering alters the genetic make-up of an organism using techniques that remove heritable material or that introduce DNA prepared outside the organism either directly into the host or into a cell that is then fused or hybridized with the host.[4] This involves using recombinant nucleic acid (DNA or RNA) techniques to form new combinations of heritable genetic material followed by the incorporation of that material either indirectly through a vector system or directly through micro-injection, macro-injection and micro-encapsulation techniques.

Genetic engineering does not normally include traditional animal and plant breeding, in vitro fertilisation, induction of polyploidy, mutagenesis and cell fusion techniques that do not use recombinant nucleic acids or a genetically modified organism in the process.[4] However the European Commission has also defined genetic engineering broadly as including selective breeding and other means of artificial selection.[5]Cloning and stem cell research, although not considered genetic engineering,[6] are closely related and genetic engineering can be used within them.[7]Synthetic biology is an emerging discipline that takes genetic engineering a step further by introducing artificially synthesized material from raw materials into an organism.[8]

If genetic material from another species is added to the host, the resulting organism is called transgenic. If genetic material from the same species or a species that can naturally breed with the host is used the resulting organism is called cisgenic.[9] Genetic engineering can also be used to remove genetic material from the target organism, creating a gene knockout organism.[10] In Europe genetic modification is synonymous with genetic engineering while within the United States of America it can also refer to conventional breeding methods.[11][12] The Canadian regulatory system is based on whether a product has novel features regardless of method of origin. In other words, a product is regulated as genetically modified if it carries some trait not previously found in the species whether it was generated using traditional breeding methods (e.g., selective breeding, cell fusion, mutation breeding) or genetic engineering.[13][14][15] Within the scientific community, the term genetic engineering is not commonly used; more specific terms such as transgenic are preferred.

Plants, animals or micro organisms that have changed through genetic engineering are termed genetically modified organisms or GMOs.[16] Bacteria were the first organisms to be genetically modified. Plasmid DNA containing new genes can be inserted into the bacterial cell and the bacteria will then express those genes. These genes can code for medicines or enzymes that process food and other substrates.[17][18] Plants have been modified for insect protection, herbicide resistance, virus resistance, enhanced nutrition, tolerance to environmental pressures and the production of edible vaccines.[19] Most commercialised GMO's are insect resistant and/or herbicide tolerant crop plants.[20] Genetically modified animals have been used for research, model animals and the production of agricultural or pharmaceutical products. They include animals with genes knocked out, increased susceptibility to disease, hormones for extra growth and the ability to express proteins in their milk.[21]

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Genetic engineering - Wikipedia, the free encyclopedia

genetic engineering,the artificial manipulation, modification, and recombination of DNA or other nucleic acid molecules in order to modify an organism or population of organisms.

The term genetic engineering initially meant any of a wide range of techniques for the modification or manipulation of organisms through the processes of heredity and reproduction. As such, the term embraced both artificial selection and all the interventions of biomedical techniques, among them artificial insemination, in vitro fertilization (e.g., test-tube babies), sperm banks, cloning, and gene manipulation. But the term now denotes the narrower field of recombinant DNA technology, or gene cloning (see Figure), in which DNA molecules from two or more sources are combined either within cells or in vitro and are then inserted into host organisms in which they are able to propagate. Gene cloning is used to produce new genetic combinations that are of value to science, medicine, agriculture, or industry.

DNA is the carrier of genetic information; it achieves its effects by directing the synthesis of proteins. Most recombinant DNA technology involves the insertion of foreign genes into the plasmids of common laboratory strains of bacteria. Plasmids are small rings of DNA; they are not part of the bacteriums chromosome (the main repository of the organisms genetic information). Nonetheless, they are capable of directing protein synthesis, and, like chromosomal DNA, they are reproduced and passed on to the bacteriums progeny. Thus, by incorporating foreign DNA (for example, a mammalian gene) into a bacterium, researchers can obtain an almost limitless number of copies of the inserted gene. Furthermore, if the inserted gene is operative (i.e., if it directs protein synthesis), the modified bacterium will produce the protein specified by the foreign DNA.

A key step in the development of genetic engineering was the discovery of restriction enzymes in 1968 by the Swiss microbiologist Werner Arber. However, type II restriction enzymes, which are essential to genetic engineering for their ability to cleave a specific site within the DNA (as opposed to type I restriction enzymes, which cleave DNA at random sites), were not identified until 1969, when the American molecular biologist Hamilton O. Smith purified this enzyme. Drawing on Smiths work, the American molecular biologist Daniel Nathans helped advance the technique of DNA recombination in 197071 and demonstrated that type II enzymes could be useful in genetic studies. Genetic engineering itself was pioneered in 1973 by the American biochemists Stanley N. Cohen and Herbert W. Boyer, who were among the first to cut DNA into fragments, rejoin different fragments, and insert the new genes into E. coli bacteria, which then reproduced.

Genetic engineering has advanced the understanding of many theoretical and practical aspects of gene function and organization. Through recombinant DNA techniques, bacteria have been created that are capable of synthesizing human insulin, human growth hormone, alpha interferon, a hepatitis B vaccine, and other medically useful substances. Plants may be genetically adjusted to enable them to fix nitrogen, and genetic diseases can possibly be corrected by replacing bad genes with normal ones. Nevertheless, special concern has been focused on such achievements for fear that they might result in the introduction of unfavourable and possibly dangerous traits into microorganisms that were previously free of theme.g., resistance to antibiotics, production of toxins, or a tendency to cause disease.

The new microorganisms created by recombinant DNA research were deemed patentable in 1980, and in 1986 the U.S. Department of Agriculture approved the sale of the first living genetically altered organisma virus, used as a pseudorabies vaccine, from which a single gene had been cut. Since then several hundred patents have been awarded for genetically altered bacteria and plants.

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Genetic Engineering, Stem Cell Research, and Human Cloning
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Ramble: Simelweis Taboo
I just don #39;t understand narrowmindedness. I don #39;t understand the stubborn refusal to face reality with integrity. I don #39;t understand cowardice. We each have only one life. Why squander it on timidity, prejudice and just so stories? Video referenced: "Taboos of Science" scishow youtu.be " Published on Jul 30, 2012 Hank discusses some of the taboos which have plagued scientific inquiry in the past and a few that still exist today. Like SciShow? http://www.facebook.com Follow SciShow: http://www.twitter.com References: dft.ba This video contains the following sounds from Freesound.org: "grim fart.wav" by Walter_Odington "Toilet Flush.wav" by tweeterdj science, scishow, taboo, society, culture, research, study, ignaz semmelweis, germ theory, disease, louis pasteur, antiseptic, social norms, semmelweis reflex, dean radin, noetic science, stem cell, chimaera, human cloning, clone, dolly, sheep, ethics, religion, panayiotis zavos, synthetic biology, genetic engineering, biology, genetics, mental health, gender identity, gender dysphoria, sexual orientation, physics, archaeology, human remains, spirituality, consciousness, poop, toilet, sanitation"From:rriverstone1Views:33 3ratingsTime:15:28More inPeople Blogs

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Genetic Engineering Of Mesenchymal Stem Cells
ll4.me Genetic Engineering Of Mesenchymal Stem Cells 1. Mesenchymal Stem Cell Engineering and Transplantation: An introduction; F. Aerts, G. Wagemaker- 2. Establishment and Transduction of primary human Stromal/Mesenchymal Stem Cell Monolayers; T. Meyerrose, I. Rosova, m. Dao, P. Herrbrich, G. Bauer, JA Nolta- 3. Gene Expression Profiles of Mesenchymal Stem Cells; DG Phinney- 4. In Vivo Homing and Regeneration of freshly isolated and culture Murine Mesenchymal Stem Cells; RE Ploemacher- 5. Non-human primate models of Mesenchymal Stem Cell Transplantation; SM Devine, R. Hoffman- 6. Engineering of Human Adipose-derived Mesenchymal Stem-like Cells; JK Fraser, M. Zhu, B. Strem, MH Hedrick- 7. Uncommitted Progenitors in Cultures of Bone Marrow-derived Mesenchymal Stem Cells; JJ Minguell, A. Rices, WD Sierralta- 8. Bone Marrow Mesenchymal Stem Cell Transplantation for Children with severe Osteogenesis Imperfecta; EM Horwitz, PL Gordon- 9. Clinical Trials of Human Mesenchymal Stem Cells to support Hematopoietic Stem Cell Transplantation; ON Ko EAN/ISBN : 9781402039591 Publisher(s): Springer Netherlands Discussed keywords: Stammzelle Format: ePub/PDF Author(s): Nolta, Jan A. 1. Mesenchymal Stem Cell Engineering and Transplantation: An introduction; F. Aerts, G. Wagemaker- 2. Establishment and Transduction of primary human Stromal/Mesenchymal Stem Cell Monolayers; T. MeyerFrom:jonibishop696Views:0 0ratingsTime:00:12More inPeople Blogs

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