Two patterns of variation among MHC class I loci in tuatara (Sphenodon punctatus)

26Citations
Citations of this article
57Readers
Mendeley users who have this article in their library.

This article is free to access.

Abstract

The genes of the major histocompatibility complex (MHC) are a central component of the immune system in vertebrates and have become important markers of functional, fitness-related genetic variation. We have investigated the evolutionary processes that generate diversity at MHC class I genes in a large population of an archaic reptile species, the tuatara (Sphenodon punctatus), found on Stephens Island, Cook Strait, New Zealand. We identified at least 2 highly polymorphic (UA type) loci and one locus (UZ) exhibiting low polymorphism. The UZ locus is characterized by low nucleotide diversity and weak balancing selection and may be either a nonclassical class I gene or a pseudogene. In contrast, the UA-type alleles have high nucleotide diversity and show evidence of balancing selection at putative peptide-binding sites. Twenty-one different UA-type genotypes were identified among 26 individuals, suggesting that the Stephens Island population has high levels of MHC class I variation. UA-type allelic diversity is generated by a mixture of point mutation and gene conversion. As has been found in birds and fish, gene conversion obscures the genealogical relationships among alleles and prevents the assignment of alleles to loci. Our results suggest that the molecular mechanisms that underpin MHC evolution in nonmammals make locus-specific amplification impossible in some species. © The American Genetic Association. 2007. All rights reserved.

Cite

CITATION STYLE

APA

Miller, H. C., Andrews-Cookson, M., & Daugherty, C. H. (2007). Two patterns of variation among MHC class I loci in tuatara (Sphenodon punctatus). Journal of Heredity, 98(7), 666–677. https://doi.org/10.1093/jhered/esm095

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free