Pathogen richness and abundance predict patterns of adaptive major histocompatibility complex variation in insular amphibians |
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Authors: | Supen Wang Conghui Liu Anthony B. Wilson Na Zhao Xianping Li Wei Zhu Xu Gao Xuan Liu Yiming Li |
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Affiliation: | 1. Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China;2. University of Chinese Academy of Sciences, Beijing, China;3. Department of Biology, Brooklyn College and The Graduate Center, City University of New York, Brooklyn, NY, USA;4. CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China |
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Abstract: | The identification of the factors responsible for genetic variation and differentiation at adaptive loci can provide important insights into the evolutionary process and is crucial for the effective management of threatened species. We studied the impact of environmental viral richness and abundance on functional diversity and differentiation of the MHC class Ia locus in populations of the black‐spotted pond frog (Pelophylax nigromaculatus), an IUCN‐listed species, on 24 land‐bridge islands of the Zhoushan Archipelago and three nearby mainland sites. We found a high proportion of private MHC alleles in mainland and insular populations, corresponding to 32 distinct functional supertypes, and strong positive selection on MHC antigen‐binding sites in all populations. Viral pathogen diversity and abundance were reduced at island sites relative to the mainland, and islands housed distinctive viral communities. Standardized MHC diversity at island sites exceeded that found at neutral microsatellites, and the representation of key functional supertypes was positively correlated with the abundance of specific viruses in the environment (Frog virus 3 and Ambystoma tigrinum virus). These results indicate that pathogen‐driven diversifying selection can play an important role in maintaining functionally important MHC variation following island isolation, highlighting the importance of considering functionally important genetic variation and host–pathogen associations in conservation planning and management. |
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Keywords: |
Ambystoma tigrinum virus
Frog virus 3
genetic drift island biogeography Major histocompatibility complex pathogen‐mediated selection population bottleneck |
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