Major histocompatibility complex class I loci from the gray whale (Eschrichtius robustus)

Sequences from exons encoding the peptide binding region of MHC class I (MHC-I) molecules were isolated from California gray whale (Eschrichtius robustus) genomic DNA to initiate an investigation of variation in these genes in a cetacean. These represent the first mysticete MHC-I sequences to be reported. The analysis of gray whale MHC-I sequences suggests the presence of at least three loci, which share greatest similarity to MHC-I in the ungulates, consistent with current views on cetacean phylogenetics. The peptide binding region of MHC is the most polymorphic part of the molecule and analysis of the variation and synonymous to nonsynonymous substitution ratios in gray whale sequences found these genes to display polymorphism characteristics similar to that attributed to selection in other species.