History of Genetics: The First Genetically Engineered Organism

The definition of genetic engineering is that it is a technology involving the direct manipulation of genes in an organism. It’s thought that the term was first coined in 1941 by A. Jost, a Danish microbiologist who was giving a lecture in Poland on the reproduction of yeast. Though there were many important developments in the years that followed, not least the discovery of the structure of DNA by Crick and Watson, it wasn’t until the early 1970’s that genetic engineering really took off. And it’s largely thanks to two American scientists.

Herb Boyer and Stanley Cohen were both working on separate, but as it turned out, complementary fields. Boyer, of the University of California at San Francisco was beavering away with enzymes that his lab had recently isolated that were able to precisely cut DNA sequences. Cohen, from Stanford University was busy with plasmids, free floating homes of DNA in bacteria. He had been extracting them from cells and then placing them in others to work out how they made bacteria resistant to antibiotics.

They scientific pair met at a conference in Hawaii in 1972. They realised their work had much in common and so they started a fruitful collaboration, developing recombinant DNA technology. Both realised the potential advantages of genetic engineering.

Boyer and Cohen showed that it was possible to directly shunt genes around from one organism to another. First of all Cohen had previously shown that E. coli could take up a plasmid that conferred resistance to an antibiotic called tetracycline. Then with his new partner they were able to precisely cut this plasmid and splice in another antibiotic resistant gene. This one was resistant to kanamycin. This plasmid vector was then taken up by E.coli which then expressed both antibiotic resistant genes - as did subsequent generations of bacteria.

The scientists repeated their experiments with other bacterial species but it was when they introduced genes from a toad into bacteria that the scientific world really sat up and took notice.

They demonstrated that a gene encoding for ribosomal RNA in the African clawed toad Xenopus laevis could be spliced into bacterial cells and expressed in all subsequent generations.

The advantages of genetic engineering were clear for all to see. Bacteria, with their generation times of about 20 minutes could be used to rapidly produce large scale quantities of beneficial proteins from higher organisms such as humans, which reproduce less frequently.

From that moment on the field of genetic engineering grew exponentially right up to the many developments, advances and innovations that we see in the present day.

The pros and cons of genetic engineering http://www.brighthub.com/science/genetics/articles/15678.aspx