Diversity and selection of MHC class I genes in the vulnerable Chinese egret (Egretta eulophotes)

PLoS One. 2017 May 3;12(5):e0176671. doi: 10.1371/journal.pone.0176671. eCollection 2017.

Abstract

The genes of major histocompatibility complex (MHC) are important to vertebrate immune system. In this study, two new MHC class I genes, designated as Egeu-UAA and Egeu-UBA, were discovered in the vulnerable Chinese egret (Egretta eulophotes). Using a full length DNA and cDNA produced by PCR and RACE methods, these two MHC class I loci were characterized in the genome of the Chinese egret and were also found to be expressed in liver and blood. Both new genes showed the expected eight exons and were similar to two copies of the minimal essential MHC complex of chicken. In genetic diversity, 14 alleles (8 for UAA and 6 for UBA) in the MHC class I gene exon 3 were found in 60 individuals using locus-specific primers and showed little polymorphism. Only three potential amino acid residues were detected under positive selection in potential peptide-binding regions (PBRs) by Bayesian analysis. These new results provide the fundamental basis for further studies to elucidate the molecular mechanisms and significance of MHC molecular adaptation in vulnerable Chinese egret and other ardeids, finding that have not been previously reported.

MeSH terms

  • Alleles
  • Amino Acid Sequence
  • Animals
  • Birds / genetics*
  • DNA / genetics
  • Endangered Species*
  • Genes, MHC Class I / genetics*
  • Genetic Variation
  • Genome / genetics
  • Polymorphism, Genetic / genetics
  • Sequence Alignment

Substances

  • DNA

Grants and funding

This research was supported by the National Natural Science Foundation of China (http://www.nsfc.gov.cn) (Grant #41476113 to XC, and 41676123 to WF), the Fujian Natural Science Foundation of China (http://xmgl.fjkjt.gov.cn/) (Grant #2010Y2007 to XC), and the Ministry of Science and Technology of China (http://service.most.gov.cn/) (Grant #2016YFC0602900 to XC). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.