Heretical DNA Sequences?

摘要

When "Genomic Clues To Dna Treasure sometimes lead nowhere" (D. Monroe, NewsrnFocus, 10 July, p. 142), the apparent impasse should indeed stimulate more subtle interpretation. Exceptions to the "conservation equals function" rule for sequence evolution are "heretical" only when mutations are expected to occur at random and to be rejected by selection in functional sequences while accumulating unchecked elsewhere. However, that simplistic view is untenable (7). Intragenomic, site-specific mutation rates vary across orders of magnitude. Sequences critical for adaptation may well have higher-than-average mutation rates, leading to rapid divergence even among closely related species.