Allelic diversity and patterns of selection at the major histocompatibility complex class I and II loci in a threatened shorebird, the Snowy Plover ( Charadrius nivosus )

BMC Evolutionary Biology

article

Cruz-López, Medardo¹  Burke, Terry²  Küpper, Clemens³  Fernández, Guillermo⁴  Hipperson, Helen²  Palacios, Eduardo⁵  Cavitt, John⁶  Galindo-Espinosa, Daniel⁷  Gómez del Angel, Salvador¹  Pruner, Raya⁸  Gonzalez, Oscar⁹ 

[1] Universidad Nacional Autónoma de México;Department of Animal and Plant Sciences, University of Sheffield;Max Planck Institute for Ornithology;Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México;Centro de Investigación Científica y de Educación Superior de Ensenada, Unidad La Paz;Avian Ecology Laboratory Department of Zoology, Weber State University;Departamento Académico de Ciencias Marinas y Costeras, Universidad Autónoma de Baja California Sur;Fish and Wildlife Research Institute;Grupo Aves del Perú;Department of Natural Sciences, Emmanuel College

关键词: Major histocompatibility complex (MHC);    Balancing selection;    Peptide-binding region (PBR);    MHC class I;    MHC class II;    Private alleles;    Charadrius;   

DOI  :  10.1186/s12862-020-01676-7

学科分类：护理学

来源: BioMed Central

【 摘 要 】

Understanding the structure and variability of adaptive loci such as the major histocompatibility complex (MHC) genes is a primary research goal for evolutionary and conservation genetics. Typically, classical MHC genes show high polymorphism and are under strong balancing selection, as their products trigger the adaptive immune response in vertebrates. Here, we assess the allelic diversity and patterns of selection for MHC class I and class II loci in a threatened shorebird with highly flexible mating and parental care behaviour, the Snowy Plover (Charadrius nivosus) across its broad geographic range. We determined the allelic and nucleotide diversity for MHC class I and class II genes using samples of 250 individuals from eight breeding population of Snowy Plovers. We found 40 alleles at MHC class I and six alleles at MHC class II, with individuals carrying two to seven different alleles (mean 3.70) at MHC class I and up to two alleles (mean 1.45) at MHC class II. Diversity was higher in the peptide-binding region, which suggests balancing selection. The MHC class I locus showed stronger signatures of both positive and negative selection than the MHC class II locus. Most alleles were present in more than one population. If present, private alleles generally occurred at very low frequencies in each population, except for the private alleles of MHC class I in one island population (Puerto Rico, lineage tenuirostris). Snowy Plovers exhibited an intermediate level of diversity at the MHC, similar to that reported in other Charadriiformes. The differences found in the patterns of selection between the class I and II loci are consistent with the hypothesis that different mechanisms shape the sequence evolution of MHC class I and class II genes. The rarity of private alleles across populations is consistent with high natal and breeding dispersal and the low genetic structure previously observed at neutral genetic markers in this species.

【 授权许可】

CC BY|CC0