The evolution of the major histocompatibility complex in upstream versus downstream river populations of the longnose dace.

Autor: Crispo E; Department of Biological Sciences University of Calgary Calgary AB Canada., Tunna HR; Department of Biological Sciences University of Calgary Calgary AB Canada., Hussain N; Department of Biology Pace University New York NY USA.; Present address: Touro College of Pharmacy New York NY USA., Rodriguez SS; Department of Biology Pace University New York NY USA.; Present address: Developmental Biology Sloan-Kettering Institute New York NY USA., Pavey SA; University of New Brunswick Saint John & Canadian Rivers Institute Saint John NB Canada., Jackson LJ; Department of Biological Sciences University of Calgary Calgary AB Canada., Rogers SM; Department of Biological Sciences University of Calgary Calgary AB Canada.
Jazyk: angličtina
Zdroj: Ecology and evolution [Ecol Evol] 2017 Apr 01; Vol. 7 (10), pp. 3297-3311. Date of Electronic Publication: 2017 Apr 01 (Print Publication: 2017).
DOI: 10.1002/ece3.2839
Abstrakt: Populations in upstream versus downstream river locations can be exposed to vastly different environmental and ecological conditions and can thus harbor different genetic resources due to selection and neutral processes. An interesting question is how upstream-downstream directionality in rivers affects the evolution of immune response genes. We used next-generation amplicon sequencing to identify eight alleles of the major histocompatibility complex (MHC) class II β exon 2 in the cyprinid longnose dace ( Rhinichthys cataractae ) from three rivers in Alberta, upstream and downstream of municipal and agricultural areas along contaminant gradients. We used these data to test for directional and balancing selection on the MHC. We also genotyped microsatellite loci to examine neutral population processes in this system. We found evidence for balancing selection on the MHC in the form of increased nonsynonymous variation relative to neutral expectations, and selection occurred at more amino acid residues upstream than downstream in two rivers. We found this pattern despite no population structure or isolation by distance, based on microsatellite data, at these sites. Overall, our results suggest that MHC evolution is driven by upstream-downstream directionality in fish inhabiting this system.
Databáze: MEDLINE
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