Genetically Modified Organisms

(Introduction)

A genetically modified organism (GMO) or genetically engineered organism (GEO) is an organism whose genetic material has been altered using genetic engineering techniques. These techniques, generally known as recombinant DNA technology, use DNA molecules from different sources, which are combined into one molecule to create a new set of genes. This DNA is then transferred into an organism, giving it modified or novel genes. Transgenic organisms, a subset of GMOs, are organisms which have inserted DNA that originated in a different species. GMOs are the constituents of genetically modified foods.

Definition

Genetic modification involves the insertion or deletion of genes. When genes are inserted, they usually come from a different species, which is a form of horizontal gene transfer. In nature this can occur when exogenous DNA penetrates the cell membrane for any reason. To do this artificially may require attaching the genes to a virus or just physically inserting the extra DNA into the nucleus of the intended host with a very small syringe, or with very small particles fired from a gene gun. However, other methods exploit natural forms of gene transfer, such as the ability of Agrobacterium to transfer genetic material to plants, or the ability of lentiviruses to transfer genes to animal cells.

Production

Three persons contributed to the breakthrough of Genetically altered Organisms . They are Paul Berg, Robert Boyer and Stanley Cohen.

In 1959 Berg joined the faculty of Stanford University. There he became interested in the genetics of microbes and took a leave to study at Renato Dulbecco’s laboratory at the Salk Institute, where he learned the techniques of animal-cell culture.

History

1.) The first step of Berg’s experiment the loops were each cut in one place by an enzyme, EcoRI.

2.) Next, to make the ends of these now-linear molecules stick together again, they were modified by two other enzymes using a procedure developed by Stanford colleagues.

3.)Then the two types of DNA were mixed together where they rejoined into loops in such a way that the new loops combined DNA from each source.

Berg did not immediately take the step of introducing the rDNA into another organism because of the public controversy over the potential dangers of such experimentation. The fear was that rDNA carrying a dreaded gene—for example, for the creation of cancerous tumors—might escape the laboratory in some common bacteria and be spread everywhere.

As chair of the National Academy of Science’s Committee on Recombinant DNA Molecules, Berg played an active role in the debate among scientists and with the public about potential limitations on such research. In the 1970s the National Institutes of Health issued guidelines for the safe conduct of rDNA research. Over time these guidelines have been eased, as more experience has shown the hazards to be far less than imagined.

The next landmark in the development of modern biotechnology was the insertion of rDNA into bacteria in such a way that the foreign DNA would replicate naturally. This step was taken in 1972 by Herbert Boyer at the University of California at San Francisco (UCSF), in collaboration with Stanley Cohen of Stanford University.

In 1972 researchers, including Herbert Boyer, realized that the enzyme EcoRI, which had actually been discovered in Boyer’s UCSF lab, cut DNA in such a way that the ends were not blunt but staggered, so that no molecular additions were needed to make one severed piece latch on to another piece possessing complementary cuts. Boyer and a colleague, Robert Helling, began their effort to create rDNA to insert in the bacteria Escherichia coli (E. coli) by trying to use EcoRI to open up the DNA of the bacterial virus lambda. They became frustrated, however, when the enzyme cut the DNA in five places instead of one, as desired.

November 1972 found both Boyer and Cohen in Hawaii giving papers at a U.S.-Japan joint meeting on plasmids. A plasmid is DNA, found especially in bacteria, that is physically separate from, and can replicate independently of, the bacterium’s chromosomal DNA. While Boyer was describing his data showing the nature of the DNA ends generated by EcoRI cleavage, Cohen was reporting on a procedure recently discovered in his laboratory that enabled bacteria to take up plasmid DNA and produce offspring that contained self-replicating plasmids identical to the original implant—clones. Over sandwiches late one night at the conference, the two men laid plans for a collaborative project to discover what genes are present on plasmids and how they are arranged.

In 1968 he accepted an appointment at the Stanford University School of Medicine.

The collaboration between Boyer and Cohen was very close. Plasmids isolated at Stanford were transported to Boyer’s lab in San Francisco for cutting by EcoRI and for analysis of the DNA fragments. These were transported back to Stanford, where they were joined and introduced into E. coli, where they multiplied.

The first success of the Boyer-Cohen collaboration occurred in spring 1973 and involved one of Cohen’s plasmids, pSC101. Plasmids were already known to transfer drug resistance among bacteria, and this one could make E. coli resistant to the antibiotic tetracycline.

Boyer and Cohen, as well as other scientists involved in cloning experimentation, soon recognized the feasibility of using bacteria into which human genetic information was incorporated to duplicate the body’s natural means of fighting disease and to remedy birth disorders.

In fall 1977, even before Genentech had its own facilities, Boyer at UCSF and Keiichi Itakura at the City of Hope Medical Center in Duarte, California, succeeded in expressing a mammalian protein in bacteria—somatostatin. This hormone, produced in the human brain, plays a major role in regulating the growth hormone. Recombinant somatostatin was shown to be virtually identical to the naturally occurring substance.

In 1978 Boyer and Itakura also constructed a plasmid that coded for human insulin. By then they had many rivals, some of them small start-ups backed by large pharmaceutical companies. In the case of recombinant insulin, Eli Lilly and Company signed a joint-venture agreement with Genentech to develop the production process for Humulin. In 1982 Humulin was approved by the FDA, and it became the first biotechnology product to appear on the market.

During the late 1970’s, researchers used recombinant DNA to engineer bacteria to produce small quantities of insulin and interferon.

One of the key scientific figures that attempted to highlight the promising aspects of genetic engineering was Joshua Lederberg, a Stanford professor and Nobel laureate.

In 1980, green genetic engineering was born. Genetic material is introduced into cell cultures for the first time ever with the aid of Agrobacterium tumefaciens.

In 1982, The U.S Food and Drug Administration approve the first genetically engineered drug, Genentech’s Humulin, a form of human insulin produced by bacteria.

In 1987, the first field tests of genetically engineered crops (tobacco and tomato) are conducted in the United States. Committee of the national Academy of Sciences concluded that transferring genes between species of organisms posed no serious environmental hazards.

In year 2000, International Biosafety Protocol is approved by 130 countries at the Convention on Biological Diversity in Montreal, Canada. The protocol agrees upon labeling of genetically engineered crops.

1. Harvard molecular geneticists Philip Leder and Timothy Stewart was awarded the first patent for a genetically altered animal which is a mouse that is highly susceptible to breast cancer.

Did You Know that..?

2. The first GMO pet is the GloFish(GlowFish)

- GloFish was essentially a zebra-fish that had been modified with bright red, green and orange fluorescent colors. The purpose of this experiment was to produce a fish that could be used to detect pollutants and environmental toxins. The development of a fluorescent fish needed to be completed first in order to continue the experiment. The fish would fluoresce in the presence of toxins.

3. The 1st non-food GMO is the Tobacco.Tobacco that is less with nicotine and resistant to pest.

4. When did people got idea of GMO?- Since the 1900s.Gatherers find food from plants they find in nature, and farmers plant seeds saved from domesticated crops. Foods are manipulated through the use of yeast and fermentation.... Some naturalists and farmers begin to recognize "hybrids," plants produced through natural breeding between related varieties of plants.

Thank You.!