Gene pseudogenization in fertility-associated genes in cheetah (Acinonyx jubatus), a species with long-term low effective population size

Abstract

The ongoing global biodiversity crisis is placing an increasing number of mammalian populations at risk of decline. Species that have survived severe historic bottlenecks, such as the cheetah (Acinonyx jubatus) exhibit symptoms of inbreeding depression including reproductive and developmental defects. Although it has long been suggested that such defects stem from an accumulation of weakly deleterious mutations, the implications of such mutations leading to pseudogenization has not been assessed. Here, we use comparative analysis of eight felid genomes to better understand the impacts of deleterious mutations in the cheetah. We find novel pseudogenization events specific to the cheetah. Through careful curation, we identify 89 genes with previously unreported premature termination codons that likely affect gene function, 65 of which are caused by point mutations. With the addition of population data, we find 22 PTCs fixed in wild populations, four of which (DEFB116, ARL13A, CFAP119 and NC5TD4) are also found in a more recent reference genome. Mutations within three of these genes are linked with sterility, including azoospermia, which is common in cheetahs. Our results highlight the power of comparative genomic approaches for the discovery of novel causative variants in declining species.