Evidence for extended positive selection in Latimeria t2r genes. Selective pressure for individual codons is shown as consensus of single likelihood ancestor counting (SLAC) and fixed effects likelihood (FEL) algorithm as implemented on the datamonkey server . A) Number of positively and negatively selected sites (p < 0.1) for six clades depicted in Figure 1; tel, 7 teleost T2Rs; Lc, 76 Lc_T2Rs; Xt, 49 Xt_T2Rs; 5 ORA2; 5 ORA4, 9 Lc_V1Rs; 12 Xt_V1Rs. B-D) Results for T2R clades are presented as snake plot (negative selection in blue, p < 0.1, neutral selection in gray, positive selection in red, p < 0.1). B) Latimeria T2R sequences. Twentyeight codons show evidence for positive selection both with SLAC and FEL algorithms. C) Teleost T2R sequences. No evidence for positive selection. D) Frog T2R sequences. Fourteen codons show evidence for positive selection with both algorithms.