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 do 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.

中文翻译：

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鲸类中的免疫球蛋白，MHC和T细胞受体基因

鲸类动物对应于已返回海洋环境的哺乳动物。随着肢体转变为鳍状肢，适应性变化非常重要。研究了免疫球蛋白，MHC I和II类以及T细胞受体基因中发生的变化。免疫球蛋白的恒定区与其余哺乳动物的恒定区相似。IgD基因是一个例外，它由三个CH结构域组成，但CH1与免疫球蛋白M的CH1相似。在IGHV基因座中，在氏族I内不存在基因的情况下，VH基因的数量减少了。 Vλ基因大于Vκ基因。在T淋巴细胞受体的基因中，存在Vα基因的数量减少，显着进化枝和亚进化枝丢失。在Vβ和Vγ中，也没有进化枝的丢失。Vα的下降，Vβ和Vγ不存在木偶藻，并且它们对鲸类具有特异性。在MHC中，存在I类基因的进化树。这些物种具有DQ，DR，DO和DM基因，但它们不存在DP基因。