Give and take: Effects of genetic admixture on mutation load in endangered Florida panthers

Genetic admixture is a biological event inherent to genetic rescue programs aimed at the long-term conservation of endangered wildlife.  Although the success of such programs can be measured by the increase in genetic diversity and fitness of subsequent admixed individuals, predictions supporting admixture costs to fitness due to the introduction of novel deleterious alleles are necessary. Here, we analyzed nonsynonymous variation from conserved genes to quantify and compare levels of mutation load (i.e., proportion of deleterious alleles and genotypes carrying these alleles) among endangered Florida panthers and non-endangered Texas pumas. Specifically, we used canonical (i.e., non-admixed) Florida panthers, Texas pumas, and F1 (canonical Florida x Texas) panthers dating from a genetic rescue program and Everglades National Park panthers with Central American ancestry resulting from an earlier admixture event. We found neither genetic drift nor selection significantly reduced overall p...