T.J. Xu, Y.N. Sun, R.X. Wang
Published: January 18, 2011
Genet. Mol. Res. 10(1): 53-64
DOI: https://doi.org/10.4238/vol10-1gmr960
Cite this Article:
T.J. Xu, Y.N. Sun, R.X. Wang (2011). Allelic polymorphism, gene duplication and balancing selection of the MHC class II DAB gene of Cynoglossus semilaevis (Cynoglossidae). Genet. Mol. Res. 10(1): 53-64. https://doi.org/10.4238/vol10-1gmr960
About the Authors
T.J. Xu, Y.N. Sun, R.X. Wang
Corresponding Author: R.X. Wang
Email: wangrixin1123@126.com
ABSTRACT
Major histocompatibility complex (MHC) genes play an important role in the immune response of vertebrates. Allelic polymorphism and evolutionary mechanism of MHC genes have been investigated in many mammals, but much less is known in teleosts. We examined the polymorphism, gene duplication and balancing selection of the MHC class II DAB gene of the half-smooth tongue sole (Cynoglossus semilaevis); 23 alleles were found in this species. Gene duplication manifested as three to six distinct sequences at each domain in the same individuals. Non-synonymous substitutions occurred at a significantly higher frequency than synonymous substitutions in the PBR domain, suggesting balancing selection for maintaining polymorphisms at the MHC II DAB locus. Many positive selection sites were found to act very intensely on antigen-binding sites of MHC class II DAB gene.
Key words: Major histocompatibility complex, Cynoglossus semilaevis, Allelic polymorphism, Balancing selection.