Egernia stokesii (gidgee skink) MHC I positively selected sites lack concordance with HLA peptide binding regions
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Genes of the major histocompatibility complex (MHC) play an important role in vertebrate disease resistance, kin recognition and mate choice. Mammalian MHC is the most widely characterised of all vertebrates, and attention is often given to the peptide binding regions of the MHC because they are presumed to be under stronger selection than non-peptide binding regions. For vertebrates where the MHC is less well understood, researchers commonly use the amino acid positions of the peptide binding regions of the human leukocyte antigen (HLA) to infer the peptide binding regions within the MHC sequences of their taxon of interest. However, positively selected sites within MHC have been reported to lack correspondence with the HLA in fish, frogs, birds and reptiles including squamates. Despite squamate diversity, the MHC has been characterised in few snakes and lizards. The Egernia group of scincid lizards is appropriate for investigating mechanisms generating MHC variation, as their inclusion will add a new lineage (i.e. Scincidae) to studies of selection on the MHC. We aimed to identify positively selected sites within the MHC of Egernia stokesii and then determine if these sites corresponded with the peptide binding regions of the HLA. Six positively selected sites were identified within E. stokesii MHC I, only two were homologous with the HLA. E. stokesii positively selected sites corresponded more closely to non-lizard than other lizard taxa. The characterisation of the MHC of more intermediate taxa within the squamate order is necessary to understand the evolution of the MHC across all vertebrates.
KeywordsMHC Peptide binding region Positively selected sites Squamata Scincidae Egernia stokesii
We thank volunteers for assistance with field surveys; Kathy Saint and Terry Bertozzi for assistance with laboratory work; and Katina Krasnec for assistance with bioinformatics. We undertook laboratory components of this work at the South Australian Research Facility for Molecular Ecology and Evolution, Adelaide. Funding from The Field Naturalists Society of South Australia and the Sir Mark Mitchell Research Foundation supported this work.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All applicable international, national, and/or institutional guidelines for the care and use of animals were followed. All procedures performed in studies involving animals were in accordance with the ethical standards of the institution at which the studies were conducted.
- Ansari TH (2016) The distribution of genetic variation in sleepy lizards. Flinders University of South Australia, AdelaideGoogle Scholar
- Benjamini Y, Hochberg Y (1995) Controlling the false discovery rate: a practical and powerful approach to multiple testing. J R Stat Soc Ser B Methodol 57:289–300Google Scholar
- Cogger HG (1983) Reptiles and amphibians of Australia. AH & AW Reed Pty Ltd, SydneyGoogle Scholar
- Díez-Rivero CM, Reche P (2009) Discovery of conserved epitopes through sequence variability analyses. In: Bioinformatics for immunomics. Springer, New York, pp. 95–101Google Scholar
- Elbers JP, Taylor SS (2016) Major histocompatibility complex polymorphism in reptile conservation. Herpetol Conserv Biol 11:1–12Google Scholar
- Hung A (2013) MHC and mate choice in Anolis sagrei. Dissertation, The University of New Mexico, AlbuquerqueGoogle Scholar
- Miller HC, O’Meally DO, Ezaz T, Amemiya C, Marshall-Graves JA, Edwards S (2015) Major histocompatibility complex genes map to two chromosomes in an evolutionarily ancient reptile, the tuatara Sphenodon punctatus. G3: Genes, Genomes, Genetics doi: 10.1534/g3.115.017467
- Pechouskova E, Dammhahn M, Brameier M, Fichtel C, Kappeler PM, Huchard E (2015) MHC class II variation in a rare and ecological specialist mouse lemur reveals lower allelic richness and contrasting selection patterns compared to a generalist and widespread sympatric congener. Immunogenet 67:229–245CrossRefGoogle Scholar
- Sommer S, Courtiol A, Mazzoni CJ (2013) MHC genotyping of non-model organisms using next-generation sequencing: a new methodology to deal with artefacts and allelic dropout. BMC Genomics 14. doi: 10.1186/1471-2164-14-542
- Stein J (1999) An ecological study of the blood parasites of E. stokesii. Dissertation, Flinders University of South Australia, AdelaideGoogle Scholar
- Strandh M, Westerdahl H, Pontarp M, Canback B, Dubois M-P, Miquel C, Taberlet P, Bonadonna F (2012) Major histocompatibility complex class II compatibility, but not class I, predicts mate choice in a bird with highly developed olfaction. Proc R Soc Lond Ser B Biol Sci 279:4457–4463CrossRefGoogle Scholar
- The Reptile Database (2015) http://www.reptile-database.org. Accessed 3 Jun 2016
- Uetz P (2015) (editor) The Reptile Database. http://www.reptile-database.org. Accessed 3 Jun 2016