Rapid Evolution of the MH Class I Locus Results in Different Allelic Compositions in Recently Diverged Populations of Atlantic Salmon.

S. Consuegra, H. -. J. Megens, H. Schaschl, K. Leon, Rene Josephus Maria Stet, W. C. Jordan

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    38 Citations (Scopus)

    Abstract

    We compared major histocompatibility class I allelic diversity in two currently reproductively isolated Atlantic salmon (Salmo salar) populations (Irish and Norwegian) with a common postglacial origin in order to test for among-population differences in allelic composition and patterns of recombination and point mutation. We also examined the evidence for adaptive molecular divergence at this locus by analyzing the rate of amino acid replacement in relation to a neutral expectation. Contrary to our prediction, and in contrast to the situation for other genetic markers, the two populations have almost nonoverlapping sets of major histocompatibility class I alleles. Although there is a strong signal of point mutation that predates population divergence, recent recombination, acting in similar, but not identical, ways in both populations appears to be a significant force in creating new alleles. Moreover, selection acting on peptide-binding residues seems to favor new recombinant alleles and is likely to be responsible for the rapid divergence between populations.

    Original languageEnglish
    Pages (from-to)1095-1106
    Number of pages11
    JournalMolecular Biology and Evolution
    Volume22
    DOIs
    Publication statusPublished - 2005

    Keywords

    • MHC
    • recombination
    • positive selection
    • Atlantic salmon
    • Salmo salar
    • MAJOR HISTOCOMPATIBILITY COMPLEX
    • AMINO-ACID SITES
    • DETECTING POSITIVE SELECTION
    • T-CELL-RECEPTOR
    • HLA-B ALLELES
    • SALAR L.
    • LIKELIHOOD METHOD
    • GENE CONVERSION
    • FARM SALMON
    • MATE CHOICE

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