Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210046, Jiangsu, People's Republic of China.
J Genet. 2021;100.
Marine mammals are exposed to the oxidative stress induced by hypoxia/reoxygenation cycles yet resist cellular damage. The availability of high-quality genomes promises to provide insights on how this is achieved. In this study, we considered the ubiquitinconjugating enzymes (E2) gene family, genes, which encodes enzymes with critical roles in cellular physiology, including the oxidative stress response. The sperm whale was the first marine mammal with a chromosome-level genome, allowing the study of gene family repertories, phylogenetic relationships, chromosome gene organization, and other evolutionary patterns on a genomewide basis. Here, 39 genes (similar to human, including 32 intact genes, one partial gene, six pseudogenes) were identified in sperm whale genome. These genes were found on 17 chromosomes and were assigned into 23 subfamilies, 16 subgroups, and four classes based on structural characteristics and functions, phylogeny and conserved domains, respectively. Although the gene structure and motif distribution of sperm whale genes are conserved in each subfamily, motif variation and intron gain/loss may contribute to functional divergence. Segmental duplications were detected in six gene pairs, which could drive gene innovation in the sperm whale. Contrasting seven cetaceans and five terrestrial taxa, we found that cetaceans have experienced shifts in selective constraint on genes, which may contribute to oxidative stress tolerance during the adaptation to aquatic life. Our results provide the first comprehensive survey of cetacean genes.
海洋哺乳动物暴露于缺氧/复氧循环引起的氧化应激下，但能抵抗细胞损伤。高质量基因组的可用性有望提供有关如何实现这一目标的见解。在这项研究中，我们考虑了泛素结合酶（E2）基因家族， 个基因，这些基因编码在细胞生理学中具有关键作用的酶，包括氧化应激反应。抹香鲸是第一种具有染色体水平基因组的海洋哺乳动物，允许在全基因组范围内研究基因家族库、系统发育关系、染色体基因组织和其他进化模式。在这里，在抹香鲸基因组中鉴定出 39 个 基因（与人类相似，包括 32 个完整基因、1 个部分基因、6 个假基因）。这些基因位于 17 条染色体上，并根据结构特征和功能、系统发育和保守结构域分别分为 23 个亚家族、16 个亚组和 4 个类。尽管抹香鲸 基因的基因结构和基序分布在每个亚家族中都保守，但基序的变化和内含子的获得/缺失可能导致功能的分化。在 6 对基因中检测到片段重复，这可能导致抹香鲸 基因的创新。与 7 种鲸目动物和 5 种陆地分类群相比，我们发现鲸目动物的 基因受到的选择压力发生了变化，这可能有助于它们在适应水生生活过程中对氧化应激的耐受。我们的研究结果提供了鲸目动物 基因的首次全面调查。
