Selection on MHC class II supertypes in the New Zealand endemic Hochstetter’s frogReport as inadecuate

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BMC Evolutionary Biology

, 15:63

First Online: 13 April 2015Received: 11 December 2014Accepted: 27 March 2015DOI: 10.1186-s12862-015-0342-0

Cite this article as: Lillie, M., Grueber, C.E., Sutton, J.T. et al. BMC Evol Biol 2015 15: 63. doi:10.1186-s12862-015-0342-0


BackgroundThe New Zealand native frogs, family Leiopelmatidae, are among the most archaic in the world. Leiopelma hochstetteri Hochstetter’s frog is a small, semi-aquatic frog with numerous, fragmented populations scattered across New Zealand’s North Island. We characterized a major histocompatibility complex MHC class II B gene DAB in L. hochstetteri from a spleen transcriptome, and then compared its diversity to neutral microsatellite markers to assess the adaptive genetic diversity of five populations -evolutionarily significant units-, ESUs.

ResultsL. hochstetteri possessed very high MHC diversity, with 74 DAB alleles characterized. Extremely high differentiation was observed at the DAB locus, with only two alleles shared between populations, a pattern that was not reflected in the microsatellites. Clustering analysis on putative peptide binding residues of the DAB alleles indicated four functional supertypes, all of which were represented in 4 of 5 populations, albeit at different frequencies. Otawa was an exception to these observations, with only two DAB alleles present.

ConclusionsThis study of MHC diversity highlights extreme population differentiation at this functional locus. Supertype differentiation was high among populations, suggesting spatial and-or temporal variation in selection pressures. Low DAB diversity in Otawa may limit this population’s adaptive potential to future pathogenic challenges.

KeywordsConservation genetics Leiopelma hochstetteri Fragmentation Balancing selection Genetic drift AbbreviationsMHCMajor histocompatibility complex

ESUEvolutionarily Significant Unit

IUCNInternational Union for Conservation of Nature

DABMHC class II beta gene

PCRPolymerase chain reaction

SLACSingle-likelihood ancestor counting

RELRandom-effects likelihood approach

MEMEMixed effect model of evolution

SBPSingle breakpoint

EDGEEvolutionarily distinct and globally endangered

DAPCDiscriminant analysis of principle components

BICBayesian information criterion

Electronic supplementary materialThe online version of this article doi:10.1186-s12862-015-0342-0 contains supplementary material, which is available to authorized users.

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Author: Mette Lillie - Catherine E Grueber - Jolene T Sutton - Robyn Howitt - Phillip J Bishop - Dianne Gleeson - Katherine Belo


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