Trait-based predictors of genomic diversity within freshwater fish communities of the Ozarks

Abstract

Phenotypic traits modulate the fate of species interactions with one another and the environment; thus, traits directly shape the past, present, and future evolutionary trajectories of populations. As such, distinct species-specific responses to a shifting environment are widely documented in the form of distinct genetic signatures, i.e., genetic diversity, reflecting differential responses over time. While the link between genetic diversity and phenotypic traits is seemingly fundamental, it has been challenging to establish unequivocally. Across an exemplar freshwater fish metacommunity, we employ phenotypic traits to test if they are significantly related to observed genetic patterns among species. Associated traits were then used to construct trait-based predictive models of genetic diversity. We collected representative constituents of a freshwater fish community (N=31 species) sampled across 75 sites within the White River Basin (Ozark Plateau, USA). For each species, we derived three genetic diversity indices (=HS/HT/G"ST) from SNP data (N=2,000 loci) and assessed 28 phenotypic traits related to morphology, life history, and ecology. We identified a series of traits (N=2-5, depending upon the index) strongly associated with facets of genetic diversity. These were subsequently applied in predictive models that explained 31-68% of the genetic variability across species, suggesting a potential utility as an imputation tactic for data-deficient species. Our approach effectively linked species-specific traits with genetic diversity within and among populations, thereby further clarifying correlations between contemporary ecological processes, as modulated by species traits, and long-term evolutionary trajectories.