Molecular evolution: detecting selection on nucleotide sequences
Our discussion of patterns of rate variation in nucleotide substitutions makes it clear that selection happens on molecular sequences. In today's lecture we'll discuss some of the ways in which we can detect selection by looking directly at the sequence of individual genes. We'll also briefly mention one way to get a sense of how much of the allele frequency changes that occur in a population are the result of natural selection - when we have samples of allele frequencies at several different points in time.