ZFIN ID: ZDB-PUB-961014-369
Trans-species polymorphism of class II mhc loci in danio fishes
Graser, R., O'hUigin, C., Vincek, V., Meyer, A., and Klein, J.
Date: 1996
Source: Immunogenetics   44: 36-48 (Journal)
Registered Authors: Klein, Jan, Meyer, Axel, O'hUigin, Colm, Vincek, V.
Keywords: none
MeSH Terms:
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Consensus Sequence
  • DNA Primers/chemistry
  • Genes, MHC Class II*
  • Molecular Sequence Data
  • Phylogeny
  • Polymorphism, Genetic
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Sequence Homology, Nucleic Acid
  • Zebrafish/genetics*
  • Zebrafish/immunology
PubMed: 8613141 Full text @ Immunogenetics
A characteristic feature of the major histocompatibility complex (Mhc) polymorphism in mammals is the existence of allelic lineages shared by related species. This trans-species polymorphism has thus far been documented only in primates, rodents, and artiodactyls. In this communication we provide evidence that it also exists in cyprinid (bony) fishes at the class II A and B loci coding for the alpha and beta polypeptide chains of the class II alpha:beta heterodimers. The study has focused on three species of the family Cyprinidae, subfamily Rasborinae: the zebrafish (Danio rerio), the giant danio (D. malabaricus), and the pearl danio (D. albolineatus). The polymerase chain reaction was used to amplify and then sequence intron 1 and exon 2 of the class II B loci and exon 2 of the class II A loci in these species. Phylogenetic analysis of the sequences revealed the existence of allelic lineages whose divergence predates the divergence of the three species at both the A and B loci. The lineages at the B locus in particular are separated by large genetic distances. The polymorphism is concentrated in the peptide-binding region sites and is apparently maintained by balancing selection. Sharing of this unique Mhc feature by both bony fishes and mammals suggests that the main function of the Mhc (presentation of peptides to T lymphocytes) has not changed during the last 400 million years of its evolution.