Pathogen diversity is a key source of selective pressure on immune system genes, shaping molecular evolution mainly on widely distributed or migratory organisms such as cetaceans. Here, we investigated the effects of latitudinal span migration, different biomes occupation, and pathogen-mediated selection on MHC DQB locus divergence on cetaceans. We applied some evolutionary genetics methods using a dataset of 15 species and 121 sequences, and we found a trend on greater MHC divergence on tropical species when compared with either temperate or migratory species. In addition, oceanic cetaceans exhibit greater MHC divergence. Here, we show that, despite there was a correlation between the diversity of MHC DQB alleles with the distribution of organisms, the pattern of diversity found is not completely explained by pathogenic pressure, suggesting that other factors must be investigated for a better understanding of the processes related to the diversity of MHC in cetaceans.

病原体多样性是免疫系统基因选择性压力的关键来源，主要影响广泛分布或迁徙生物（例如鲸类）的分子进化。在这里，我们调查了横向跨度迁移，不同生物群落职业以及病原体介导的选择对鲸类MHC DQB位点发散的影响。我们使用了15个物种和121个序列的数据集应用了一些进化遗传学方法，并且发现与温带或迁徙物种相比，热带物种MHC差异更大。此外，大洋鲸类动物的MHC差异更大。在这里，我们表明，尽管MHC DQB等位基因的多样性与生物体分布之间存在相关性，但发现的多样性模式并不能完全由致病压力来解释，