MHC heterozygosity and survival in red junglefowl

Worley, Kirsty, Collet, Julie, Spurgin, Lewis G., Cornwallis, Charlie, Pizzari, Tommaso and Richardson, David S. (2010) MHC heterozygosity and survival in red junglefowl. Molecular Ecology, 19 15: 3064-3075. doi:10.1111/j.1365-294X.2010.04724.x

Author Worley, Kirsty
Collet, Julie
Spurgin, Lewis G.
Cornwallis, Charlie
Pizzari, Tommaso
Richardson, David S.
Title MHC heterozygosity and survival in red junglefowl
Journal name Molecular Ecology   Check publisher's open access policy
ISSN 0962-1083
Publication date 2010-08
Year available 2010
Sub-type Article (original research)
DOI 10.1111/j.1365-294X.2010.04724.x
Volume 19
Issue 15
Start page 3064
End page 3075
Total pages 12
Place of publication Oxford, United Kingdom
Publisher Wiley-Blackwell
Language eng
Formatted abstract
Genes of the major histocompatibility complex (MHC) form a vital part of the vertebrate immune system and play a major role in pathogen resistance. The extremely high levels of polymorphism observed at the MHC are hypothesised to be driven by pathogen-mediated selection. Although the exact nature of selection remains unclear, three main hypotheses have been put forward; heterozygote advantage, negative frequency-dependence and fluctuating selection. Here, we report the effects of MHC genotype on survival in a cohort of semi-natural red junglefowl (Gallus gallus) that suffered severe mortality as a result of an outbreak of the disease coccidiosis. The cohort was followed from hatching until 250 days of age, approximately the age of sexual maturity in this species, during which time over 80% of the birds died. We show that on average birds with MHC heterozygote genotypes survived infection longer than homozygotes and that this effect was independent of genome-wide heterozygosity, estimated across microsatellite loci. This MHC effect appeared to be caused by a single susceptible haplotype (CD_c) the effect of which was masked in all heterozygote genotypes by other dominant haplotypes. The CD_c homozygous genotype had lower survival than all other genotypes, but CD_c heterozygous genotypes had survival probabilities equal to the most resistant homozygote genotype. Importantly, no heterozygotes conferred greater resistance than the most resistant homozygote genotype, indicating that the observed survival advantage of MHC heterozygotes was the product of dominant, rather than overdominant processes. This pattern and effect of MHC diversity in our population could reflect the processes ongoing in similarly small, fragmented natural populations.
Keyword Heterozygote advantage
Major histocompatibility complex
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Biological Sciences Publications
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Citation counts: TR Web of Science Citation Count  Cited 41 times in Thomson Reuters Web of Science Article | Citations
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Created: Tue, 09 Apr 2013, 12:27:07 EST by Julie Collet on behalf of School of Biological Sciences