Secret on white highway and brown byway to the rose of the winds
Biologists had long known that DNA was built out of four molecules: adenine, guanine, thymine and cytosine. They assumed that these molecules occurred in equal quantity and dismissed any measurements that hinted otherwise as experimental errors.
Chargaff showed through careful measurement that this assumption was wrong. He found that the amount of adenine equalled that of thymine and the amount of guanine equalled that of cytosine but these were not equal to each other. (…)
Chargaff went on to discover that an approximate version of his rule also holds for most (but not all) single-stranded DNA. (…) Chargaff’s rules are important because they point to a kind of “grammar of biology,” a set of hidden rules that govern the structure of DNA. (…)
But in the 60 years since Chargaff discovered his invariant patterns, no others have emerged. Until now.
artwork { Robin Williams }
