Figure 6. Predicted positively selected sites in Prdm9 from divergent metazoan lineages.

Results for previously presented rodent and primate lineages are also shown here for comparison (blue shading). Positive selection was inferred for each species [27] from intra-species Prdm9 zinc finger sequence alignments. Positively selected sites (P<0.05 after multiple testing correction) are shown mapped to the third mouse Prdm9 zinc finger sequence (MMM3). The majority of positively selected sites, across 700 million years of divergence from sea anemone to mammals, fall at positions −1, 3, and 6. The inferences of positive selection for Capitella were made on the basis of three sequences on separate unassembled genomic scaffolds. Despite their high sequence similarity, multiple uncorrelated point substitutions, especially among the zinc fingers, suggest that they may represent allelic copies or rapidly diverging paralogues.