the history of molecular biology can, begotten_ be_ essentially begun with the idea of, from whence did, um, heredity come. was it originally an ethos? was it a spirit? or, um, did it have a molecular basis? and for quite a long time, many biologists honestly thought that heredity originated in proteins. and several experiments, mainly in the United States and the United Kingdom actually showed that nucleic acids, and not proteins are actually the source of heredity.
all of this, is key to understanding today's recombinant D-N-A technology. and all of the revolutions that are involved in modern day genetics. we can hon- honestly begin at the Rockefeller Institute in New York City with Oswald Avery, and Chargaff. Oswald Avery was the first to actually show, that D-N-A or nucleic acid heretofore believed to be just an extraneous bio synthetic by-product of the body's physiology. um, was responsib- was actually responsible for D-N-A. Avery's original experiment showed that if one, uh, were to take D-N-A out of a frog egg. remove its D-N-A completely through chemical means and then allow the frog egg to generate or germinate, it couldn't form a frog. whereas if the proteins in its nucleus, the center of the cell where in all of purportedly the heredity information was stored, were removed, but the nucleic acids remained, the frog could develop normally. although Avery, uh, did the crucial experiment that showed that D-N-A was of course the source of heredity, for all living things, never won the Nobel prize.
(Chargoff) was yet another_ was an East_ was an Eastern European scientist who came to the Rockefeller Institute in, in New York as well. and showed that, that D-N-A in and of itself had all of the characteristics that are actually needed for heredity. it provided information, at a level of very low entropy, that is very low disorder. it could show the repeating patterns, that there was enough uh, variability in the sequence of D-N-A_ in the chemicals that are contained within D-N-A, to provide information for even extremely complex living organisms, from very basic yeast, to, human beings that have the ability to think. a very exciting idea indeed.
but no one could really honestly think of the mechanisms of heredity, until the Englishman, Francis Crick and the American James Dewey Watson, actually discovered the structure of D-N-A. not through any, uh, direct means, not through x-ray crystallography, not through chemical, uh, identification, or any of the modern day techniques, um, that, uh, we use. or even the techniques that were contemporary to them, developed by Bragg, um, and Rosalind Franklin. but instead used very simple stick and ball models, to come up with the idea that D-N-A could, first of all by separating its two strands, opening up, uh, to the cellular environment, provide the information that was necessary for the machinery within living things, to take its information and turn it, turn it to the vital structural proteins, and vital enzymes that, organisms need to just survive.
the next step, once we have the idea that D-N-A, has a given structure and has information, um, inherent within its structure. that is it can give to the cell, um, um, through a, um, through a functional means. we have to understand how we can manipulate it. this revolution came back actually in the nineteen-seventies with Daniel Nathans and his group, at the Johns Hopkins University. who discovered that bacteria have very interesting enzymes, that allow them to destroy the D-N-A of viruses that infect them. these enzymes referred to as, restriction enzymes, allow the bacterium to go and chew up enemy D-N-A. luckily, molecular biologists realized that these very enzymes could allow them to manipulate the D-N-A, in very interesting ways. because of the nature of the enzyme, it will look at D-N-A specific codes within D-N-A. and clip only those specific codes, such that one can now cut and paste, so to speak, using the lingo of modern day Macintosh or, uh, personal computer technology, um, could cut and paste D-N-A and manipulate it. such that one could get the information from the D-N-A that one actually wants. um, this discovery of restriction enzymes along with the discovery of the structure of D-N-A_ these two discoveries were actually awarded the Nobel prize. the importance of restriction enzymes, and the importance of research that had been do uh, has been done since the nineteen-seventies, um, is crucial to recombinant D-N-A technology., such as the idea that D-N-A that has been manipulated in the test tube for the use of restriction enzymes can now be introduced into cells. and that these cells can therefore change their entire physiology, just on the basis of a simple man-made manipulation of their genetic information, has essentially caused the, massive explosion of biotechnology. this more important than anything else, um, of all of the aspects of the revolution, of molecular biology_ the economic aspect (hahm)um, has been of great interest of industry and therefore has caused a massive influx of funds, into molecular biology and has i- introduced further innovation.