Extremely high MHC class I variation in a population of a long-distance migrant, the Scarlet Rosefinch (Carpodacus erythrinus)
Abstract
We describe the structure and diversity of exon 3 of MHC class I in the Scarlet Rosefinch (Carpodacus erythrinus). Using SSCP, we identified 82 different variants in a population in the Czech Republic.
This is the highest MHC class I variation observed in birds. We have not found support for "minimal essential" MHC in this species since individuals exhibited between 3 to 9 different exon 3 sequences, indicating that there may be at least 5 amplified class I genes.
By cloning, we obtained and analysed 29 exon sequences and found that all of them could be translated into potentially functional proteins. We found that strong positive selection is acting mainly, but not only, on previously described antigen binding sites.
Also, our results indicate that recombination has played an important role in generating diversity of these genes in the Scarlet Rosefinch; we discuss the significance of this genetic diversity in light of the life history traits of this species.