Selection and demography drive range-wide patterns of MHC-DRB variation in mule deer.

Autor: Cook RM; Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, 53211, USA. cookrachel52@gmail.com., Suttner B; Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, 53211, USA.; GenoTwin, Bridgewater, MA, USA., Giglio RM; Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, 53211, USA.; USDA, Wildlife Services, National Wildlife Research Center, Wildlife Genetics Lab, Fort Collins, CO, USA., Haines ML; Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, 53211, USA.; School of Biological Sciences, Monash University, Clayton, VIC, Australia., Latch EK; Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, 53211, USA.
Jazyk: angličtina
Zdroj: BMC ecology and evolution [BMC Ecol Evol] 2022 Apr 06; Vol. 22 (1), pp. 42. Date of Electronic Publication: 2022 Apr 06.
DOI: 10.1186/s12862-022-01998-8
Abstrakt: Background: Standing genetic variation is important especially in immune response-related genes because of threats to wild populations like the emergence of novel pathogens. Genetic variation at the major histocompatibility complex (MHC), which is crucial in activating the adaptive immune response, is influenced by both natural selection and historical population demography, and their relative roles can be difficult to disentangle. To provide insight into the influences of natural selection and demography on MHC evolution in large populations, we analyzed geographic patterns of variation at the MHC class II DRB exon 2 locus in mule deer (Odocoileus hemionus) using sequence data collected across their entire broad range.
Results: We identified 31 new MHC-DRB alleles which were phylogenetically similar to other cervid MHC alleles, and one allele that was shared with white-tailed deer (Odocoileus virginianus). We found evidence for selection on the MHC including high dN/dS ratios, positive neutrality tests, deviations from Hardy-Weinberg Equilibrium (HWE) and a stronger pattern of isolation-by-distance (IBD) than expected under neutrality. Historical demography also shaped variation at the MHC, as indicated by similar spatial patterns of variation between MHC and microsatellite loci and a lack of association between genetic variation at either locus type and environmental variables.
Conclusions: Our results show that both natural selection and historical demography are important drivers in the evolution of the MHC in mule deer and work together to shape functional variation and the evolution of the adaptive immune response in large, well-connected populations.
(© 2022. The Author(s).)
Databáze: MEDLINE
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