Figure 3From: Evolution under strong balancing selection: how many codons determine specificity at the female self-incompatibility gene SRK in Brassicaceae?Intron-exon structure of SRK and sites identified as evolving under positive selection in Brassica, A. halleri and A. lyrata. Sites 270–306, 328–343, and 413–423 correspond to hypervariable regions HV2, HV3, and CVR respectively. Codons identified by more than a single species are figured in bold.Back to article page