o The bases could be adenine

o The bases could be adenine - o The bases could be adenine...

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o The bases could be adenine (A), thymine (T), guanine (G), or cytosine (C). Chargaff noted that the DNA composition varies from species to species. In any one species, the four bases are found in characteristic, but not necessarily equal, ratios. He also found a peculiar regularity in the ratios of nucleotide bases, known as Chargaff’s rules. ○ In all organisms, the number of adenines is approximately equal to the number of thymines (%T = %A). ○ The number of guanines is approximately equal to the number of cytosines (%G = %C). Human DNA is 30.3% adenine, 30.3% thymine, 19.5% guanine, and 19.9% cytosine. The basis for these rules remained unexplained until the discovery of the double helix. Watson and Crick discovered the double helix by building models to conform to X-ray data. By the beginning of the 1950s, the race was on to move from the structure of a single DNA strand to the three- dimensional structure of DNA. Among the scientists working on the problem were Linus Pauling in California and Maurice Wilkins and Rosalind
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o The bases could be adenine - o The bases could be adenine...

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