1926 - present
Genetic engineering is one of the major tools explored in the book that could influence the possible future speciation of Homo sapiens.
Paul Berg, who received the Nobel Prize in Chemistry in 1980, inaugurated the era of genetic engineering with his seminal work on nucleic acids, the building blocks of DNA. In the early 1970s, he and his colleagues at Stanford showed that it was possible to selectively take a portion of DNA from one organism and insert it into the DNA of another organism. This was the first demonstration of the creation of what is called recombinant DNA.
Based on this work, in 1973, Herb Boyer and Stanley Cohen experimented with common bacteria found in all humans, E. coli. These bacteria have structures in their cells called plasmids that are small circular pieces of DNA, separate from the chromosomes, which produce proteins in bacteria. They play a role in a small number of functions, including antibiotic resistance. Boyer and Cohen were able to transfer plasmids from one strain of E. coli having resistance to a single antibiotic into another strain that did not have that resistance. After transfer, the receiving strain subsequently had resistance also. This showed that the genes from one strain of E. coli could be transferred to another strain.
What really got the ball rolling, however, was when they showed they could selectively cut out the part of the plasmid containing the resistance gene and patch it into the plasmid of another strain of E. coli thus creating recombinant DNA with the resistance gene. This is the key to genetic engineering: the ability to isolate a small segment of an organism’s DNA that contains a particular nucleotide sequence of interest, to make many copies of that DNA segment, and then splice or patch that segment into some vector to create recombinant DNA. The vector is then used to enter the target or host organism. In this first case cited above, the vector was a bacteria plasmid. Viruses are commonly used as vectors as well. Since the recombinant DNA gene was from the same species as the host organisms, the process is called cisgenic.
Next they created a recombinant DNA plasmid that contained the genes for resistance to multiple antibiotics by patching genes from a different species of bacteria, Staphylococcus aureus, into a single E. coli plasmid, transferred that plasmid to other E. coli which then not only became resistant to all the antibiotics, but also conveyed those same traits on to future generations of that strain of E. coli. This showed that genes from a different species of bacteria could be transferred to host bacteria. When genes are passed across species, it is called transgenic. Genetic engineering was now underway.
Finally they demonstrated that they could create an E. coli recombinant DNA plasmid that contained a gene from a toad! And the toad gene functioned in all future generations of that strain of E. coli. This showed that transgenic engineering could occur virtually unconstrained by species and set the stage for human genetic engineering.
Genetic engineering is one of four major pathways to a future human species explored in the book. The other pathways are catastrophe, natural selection, and electronic evolution.
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