Vulnerability correlates with life history traits and the load of deleterious mutations in fish.

Understanding why some species accumulate more deleterious substitutions than others is an important question relevant in evolutionary biology and conservation sciences. Previous studies conducted in terrestrial taxa suggest that life history traits correlate with the efficiency of purifying selection and accumulation of deleterious mutations. Using a large genome dataset of 76 species of fishes, we show that the rate of deleterious mutation accumulation (measured via dN/dS, i.e. non-synonymous over synonymous substitution rate) is associated to the vulnerability, the life-history strategies, and the latitude of species. Our results, focusing on a large clade of aquatic species, generalizes previous patterns found so far in few clades of terrestrial vertebrates. These results also suggest that vulnerable species accumulate more deleterious substitutions than non-threatened ones, which give insights in how life-history traits, populations sizes and genetic risk of extinction can be tightly interconnected.