Comparative genomic analysis reveals phylogenetic divergence in mutation fitness effects across 11 animal species, indicating organismal complexity influences mutational harm.
Key Points
To systematically evaluate how the distribution of fitness effects of nonsynonymous mutations varies across diverse animal lineages and determine whether life-history traits drive these differences.
Inferred the distribution of fitness effects (DFE) of nonsynonymous mutations in natural populations across 11 animal (sub)species, including mammals, birds, and insects.
Quantified phylogenetic signal in the DFE using Pagel's λ and correlated DFE summary statistics against life-history metrics such as genome size, body mass, and long-term effective population size.
Mammals harbored a substantially higher proportion of strongly deleterious mutations (s ≤ -0.01; 22% to 47%) and fewer weakly deleterious mutations than insects and birds (0.0% to 5.4%).
Mean mutational fitness effects exhibited strong phylogenetic signal, with closely related species displaying significantly more similar values (Pagel's λ = 0.84, P = 0.01).
DFE variation correlated with genome size, body mass, and long-term effective population size, supporting Fisher's Geometric Model predictions regarding organismal complexity.