Evidence of genetic erosion in a peripheral population of a North American game bird: the Montezuma quail (Cyrtonyx montezumae)
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2019, Springer Nature B.V. Population extirpations are often precursors to species extinctions. Anthropogenic activities often lead to smaller populations that are more prone to extirpations and advocates for active conservation management have recently called for the preservation and monitoring of genetic diversity, particularly with regard to the adaptive potential of vulnerable populations. We used genomics and curated arrays of molecular markers, including those expected to impact key fitness traits, to quantify evidence of genomic erosion in core and peripheral populations of a gallinaceous bird. The Montezuma quail (Cyrtonyx montezumae) is a game species considered vulnerable to extirpation in Texas, but core populations in Arizona and New Mexico are robust and have the potential to serve as genetic reservoirs. We sequenced the Montezuma quail genome then developed a single nucleotide polymorphism (SNP) assay to quantify genetic variation, effective population sizes, signatures of natural selection, and population structure. We genotyped SNPs from gene deserts and from genes associated with fitness traits and found the isolated Texas population exhibits an extremely small effective population size, is genetically distinct from our Arizona and New Mexico samples, and has reduced heterozygosity at the fitness-related markers. Thus, our samples from Texas exhibit symptoms of genetic erosion that could exacerbate future risk of local extirpation. Management agencies must decide if active conservation efforts such as assisted gene flow or genetic rescue are now warranted. This decision may not be straightforward because the current conservation status of the Texas population reflects its isolated geographic locale on the periphery of the species range.
