Figure 3

Evolution rate analyses of TaMET1 genes. A) Pair-wise comparisons. Synonymous (dS), non-synonymous (dN) and evolution rate (ω) are expressed in substitution/site and were performed using Codeml. TaMET1 from wheat homoeologous group 2 (grey boxes) were compared to Brachypodium distachyon [Phytozome: Bradi1g05380 and Bradi1g55287], Sorghum bicolor [Phytozome: Sb01g005084 and Sb02g004680], Oriza sativa [Genbank: AB362510 and AB362511], Zea mays [Phytozome: GRMZM2G333916 and GRMZM2G334041], Hordeum vulgare [Ensembl Genomes: MLOC_61904.6 and: MLOC_10988.2 and GenBank: CAJW010043285] and Triticum aestivum (TaMET-2A1, 2B1, 2D1, 5A1, 5B1, 5D1, 7A1, 7B1 and 7D1) (accession numbers in Additional file 8). Mean values of dS, dN and ω (with ω = dN/dS) were then computed for each homoeologous group. Whiskers represent the 10-90% range of mean values, boxes represent interquartile distances, the horizontal line across whiskers represents the median, and “+” the mean values. Kruskal Wallis non-parametric tests were applied to determine significant differences between mean values (*: P < 0.05; **: P < 0.01; ***: P < 0.001). B) PAML branch model. Tree topology was defined by a protein alignment using the same monocot species as in A). The two monophyletic groups MET-1a and MET-1b are indicated at the right. Three distinct evolution rates ω0 (red branches), ω1 (black branches) and ω2 (blue branches) are indicated as well as the two gene duplication events described in Figure 1 (arrow).