Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu 210046, China.
Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu 210046, China. E-mail:
Zool Res. 2024 Nov 18;45(6):1209-1220. doi: 10.24272/j.issn.2095-8137.2024.029.
High-altitude and marine mammals inhabit distinct ecosystems but share a common challenge: hypoxia. To survive in low-oxygen environments, these species have evolved similar phenotypic pulmonary adaptations, characterized by a high density of elastic fibers. In this study, we explored the molecular mechanisms underlying these adaptations, focusing on pulmonary fibrosis and hypoxia tolerance through comparative genomics and convergent evolution analyses. We observed significant expansions and contractions in certain gene families across both high-altitude and marine mammals, closely associated with processes involved in pulmonary fibrosis. Notably, members of the keratin gene family, such as and , appear to be associated with the development of the dense elastic fiber phenotype observed in the lungs of hypoxia-tolerant mammals. Through selection pressure and amino acid substitution analyses, we identified multiple genes exhibiting convergent accelerated evolution, positive selection, and amino acid substitution in these species, associated with adaptation to hypoxic environments. Specifically, the convergent evolution of , , and was found to contribute to the high density of elastic fibers in the lungs of both high-altitude and marine mammals, facilitating their hypoxia tolerance. Additionally, we identified convergent amino acid substitutions and gene loss events associated with sperm development, differentiation, and spermatogenesis, such as amino acid substitutions in and pseudogenization of , as confirmed by PCR. These genetic alterations may be linked to changes in the reproductive capabilities of these animals. Overall, this study offers novel perspectives on the genetic and molecular adaptations of high-altitude and marine mammals to hypoxic environments, with a particular emphasis on pulmonary fibrosis.
高海拔和海洋哺乳动物栖息在截然不同的生态系统中，但面临着一个共同的挑战：缺氧。为了在低氧环境中生存，这些物种进化出了相似的表型肺适应特征，其特征是弹性纤维密度高。在这项研究中，我们通过比较基因组学和趋同进化分析，探讨了这些适应的分子机制，重点研究了肺纤维化和缺氧耐受。我们观察到高海拔和海洋哺乳动物的某些基因家族在数量上都有明显的扩张和收缩，这与肺纤维化过程密切相关。值得注意的是，角蛋白基因家族的成员，如 和 ，似乎与在耐缺氧哺乳动物肺部观察到的密集弹性纤维表型的发育有关。通过选择压力和氨基酸替换分析，我们鉴定出多个在这些物种中表现出趋同加速进化、正选择和氨基酸替换的基因，这些基因与对低氧环境的适应有关。具体来说， 、 和 的趋同进化被发现有助于高海拔和海洋哺乳动物肺部的高密度弹性纤维，从而促进它们对缺氧的耐受。此外，我们还发现了与精子发生、分化和精子发生相关的趋同氨基酸替换和基因缺失事件，如 中的氨基酸替换和 的假基因化，这一点通过 PCR 得到了证实。这些遗传改变可能与这些动物生殖能力的变化有关。总的来说，本研究为高海拔和海洋哺乳动物对低氧环境的遗传和分子适应提供了新的视角，特别关注肺纤维化。
