Bayesian reconstruction of unique DRA alleles in Equidae. Sequence data (243 bp) was partitioned by codon position and a GTR nucleotide substitution model was used, with equal rates across sites. Analyses were run with 6 chains for 7,000,000 generations, burnin = 17,500 trees. Posterior probabilities > 50% are reported at the nodes. Identical alleles across multiple species are indicated by the appropriate colored bars (see legend) and names were omitted from the tree: Eqbu-DRA*01 = Eqgr-DRA*02 = Eqze-DRA*02; Eqbu-DRA*04 = Eqki-DRA*02; Eqbu-DRA*07 = Eqas-DRA*01 = Eqze-DRA*01; Eqbu-DRA*08 = Eqca-DRA*04; Eqze-DRA*03 = Eqas-DRA*04; Eqbu-DRA*05 = Eqze-DRA*04; Eqbu-DRA*03 = Eqas-DRA*02 = Eqhe-DRA*02 = Eqki-DRA*01. Sequences from Bos taurus (DQ821713), Ovis aries (Z11600) and Sus scrofa (AY754888) were used as outgroups.