Hybrid plasmid of synthetic gene

1974, Cohen "assembled" the plasmid of Staphylococcus aureus (with penicillin resistance gene on it) and the plasmid of Escherichia coli into a "hybrid plasmid" and "transported" it into Escherichia coli to make Escherichia coli resistant to penicillin. This shows that the penicillin-resistant gene on Staphylococcus aureus plasmid was introduced into E.coli from "hybrid plasmid". More importantly, in the same year, he "cut" the next segment from Xenopus laevis DNA and spliced it with E.coli. The spliced plasmid entered E.coli with Xenopus laevis gene, and E.coli produced Xenopus laevis ribosomal ribonucleic acid (rRNA). Cohen became a pioneer again. The fact that amphibian genes can play a role in bacteria and can be continuously replicated in bacteria tells people that genetic engineering can completely splice genes according to human wishes to create new organisms, such as E.coli for reeling, E.coli for pharmaceutical use and so on. When Cohen succeeded for the third time, he immediately declared the world's first genetic engineering patent to the US Patent Office as the inventor of DNA recombination technology, becoming the first person to implement genetic engineering.

Cohen's first successful genetic engineering not only broke the natural barrier formed by different species in hundreds of millions of years, but also predicted that genes of any different species could be recombined through genetic engineering technology. Cohen's patent also marks that human beings can indeed directionally transform the genetic characteristics of organisms and even create new life types according to their own wishes and purposes. Cohen's patented technology caused a global sensation. In just a few years, hundreds of laboratories in many countries around the world have carried out genetic engineering research.

1970, Khorana, an Indian-American scholar, chemically synthesized 77 nucleotide pairs of yeast alanine structural genes for the first time. From 65438 to 0972, the laboratory led by Bartimore, Spegorman and Lietier used reverse transcriptase to synthesize rabbit and human globin genes, which was the first time to synthesize eukaryotic genes. 1973, Khorana succeeded again. He used 126 nucleotide pairs to synthesize tyrosine transporter RNA(tRNA) gene of Escherichia coli. In order to make the synthesized gene work, Khorana and others worked hard for three years, and finally successfully transcribed tyrosine tRNA from E.coli tyrosine transporter RNA(tRNA) gene in August of 1976.

From 65438 to 0977, Boyer of the University of California chemically synthesized the gene of human growth hormone inhibitory factor. Human growth hormone inhibitory factor is a neurohormone secreted by human brain, intestine and pancreas. It can inhibit the secretion of thyrotropin, gastrin, insulin and glucagon, and has medical value for acromegaly, acute pancreatitis and diabetes. Boyer then recombined the synthetic gene with E.coli plasmid, and the recombinant DNA was successfully introduced into E.coli. The synthetic gene produced 5 mg of Boyer's human growth hormone inhibitory factor in E.coli. This 5 mg of growth hormone inhibitory factor can be said to be a gift given to Boyer by the artificial gene. If 5 mg of growth hormone inhibitory factor is extracted from sheep by traditional methods, 500 thousand sheep heads are needed.