WGD assessment
The distribution of synonymous substitutions per site (Ks) within paralogs was used to examine the most recent WGD event in salmonids. The protein sequences of all 11 species were aligned with BLAST v2.9.0 (e-value 1e-10) (Altschul et al.1990). When one gene and another gene were mutual best hits (excluding hits to themselves), they were identified as a paralog genes. Ks was calculated using the KaKs_calculator v2.0 (Wang et al. 2010) for each paralog. For comparison, we also plotted the Ks distribution betweenB. l. tsinlingensis and other species.