Population specific SNPs. (A) Genomic nucleotide diversity, as estimated by Watterson’s (θ), for each population. Within populations, nucleotide diversity was measured for different genomic sequence classes including miRNA genes (black) which were conserved to a level comparable to exons (blue), in all populations. (B) The number of population specific miRNA alleles (PSMA) divided by the number of genomes collected for each population (shown in black). The right axis displays the number of high frequency PSMAs, with an allele frequency greater than 50% in a single population (red).