Figure 4

Frequencies of d _S and ω values for comparisons within S. salar and E. lucius gene trios. (A) Distributions of d_S values from pairwise comparisons within gene trios: between S. salar paralogs (green) and between each of the two S. salar paralogs and its corresponding E. lucius ortholog (gray and black). (B) Distributions of d_N/d_S ratios (ω) from pairwise comparisons within gene trios: between S. salar paralogs (green) and between each of the two S. salar paralogs and its corresponding E. lucius ortholog (gray and black). (C) Distributions of d_S values separated into individual tree branches based on gene trios. Values from pairwise comparisons were used to calculate silent substitution rates for periods before and after the salmonid tetraploidization event. The light blue curve represents frequencies of d_S values from the duplication event to one S. salar paralog, the red curve from the duplication event to the other paralog, and the black curve prior to the genome duplication to the E. lucius ortholog. (D) Distributions of d_N/d_S ratios separated into branches where one S. salar paralog, that which has the lower ω value, is considered to be a slow branch (light blue curve) and the other paralog (red curve) is considered to be more quickly diverging (fast branch for the purposes of labelling). The black curve displays frequencies of ω values between the E. lucius ortholog and the genome duplication.