Fig. 4

GammaMap reveals the posterior probability for positive selection coefficient at each codon using population data from the DPGP. In concordance with Wilson et al. 2011, a codon is under significant signature of selection when the posterior probabilities of selection (lines) are greater than 0.5 (primary Y-axis). Vertical bars illustrate minor allele frequencies in D. melanogaster (secondary Y-axis) and the substitutions are the circular dots. The colors correspond to D. melanogaster non-synonymous (red) and synonymous (dark green) variants as well as D. simulans non-synonymous (orange) and synonymous (light green) variants. Estimated number of selected codons is indicated in the upper right of each plot