Abstract
Cetaceans correspond to mammals that have returned to the marine environment. Adaptive changes are very significant with the conversion of the limbs into flippers. It is studied the changes that have occurred in immunoglobulins, MHC class I and II and T cell receptors genes. Constant regions of immunoglobulins are similar to those of the rest of mammals. An exception is the IgD gene, which is composed of three CH domains but CH1 similar to CH1 of immunoglobulin M. In the IGHV locus, it exist a decrease in the number of VH genes with the absence of genes within Clan I. The number of Vλ genes is greater than that of Vκ. In the genes for T lymphocyte receptors, it exists a decrease in the number of Vα genes with loss of significant clades and subclades. In Vβ and Vγ, there is also the loss of clades. These declines of Vα, Vβ and Vγ are not present Artiodactyla, and they are specific to Cetaceans. In MHC present tree evolutive lines of class I genes. These species have DQ, DR, DO and DM genes, but they are no present DP genes.
Competing Interest Statement
The authors have declared no competing interest.
