In mammals, it is usually assumed that selection cannot be strong enough to act on nucleotide mutations that do not cause a change at the protein level (i.e. 'silent' or 'synonymous' mutations). Here we report the results of a molecular evolutionary analysis of BRCA1. We find a repeatable pronounced peak in the ratio of nonsynonymous to synonymous substitutions between codons 200-300. Unusually,this peak is caused by a plummet in the silent-site rate of evolution. The most parsimonious interpretation of these data is that purifying selection is acting on silent sites.
|Number of pages||4|
|Journal||Trends in Genetics|
|Publication status||Published - 2001|