State Key Laboratory of Grassland Agro-Ecosystems, College of Pastoral Agricultural Science and Technology, Lanzhou University, Lanzhou 730020, People's Republic of China; Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture, People's Republic of China.
State Key Laboratory of Grassland Agro-Ecosystems, College of Pastoral Agricultural Science and Technology, Lanzhou University, Lanzhou 730020, People's Republic of China.
Mol Phylogenet Evol. 2018 May;122:116-124. doi: 10.1016/j.ympev.2018.01.016. Epub 2018 Feb 16.
Grassland caterpillars (Lepidoptera: Lymantriinae: Gynaephora) are the most important pests in alpine meadows of the Tibetan Plateau (TP) and have well adapted to high-altitude environments. To further understand the evolutionary history and their adaptation to the TP, we newly determined seven complete TP Gynaephora mitogenomes. Compared to single genes, whole mitogenomes provided the best phylogenetic signals and obtained robust results, supporting the monophyly of the TP Gynaephora species and a phylogeny of Arctiinae + (Aganainae + Lymantriinae). Incongruent phylogenetic signals were found among single mitochondrial genes, none of which recovered the same phylogeny as the whole mitogenome. We identified six best-performing single genes using Shimodaira-Hasegawa tests and found that the combinations of rrnS and either cox1 or cox3 generated the same phylogeny as the whole mitogenome, indicating the phylogenetic potential of these three genes for future evolutionary studies of Gynaephora. The TP Gynaephora species were estimated to radiate on the TP during the Pliocene and Quaternary, supporting an association of the diversification and speciation of the TP Gynaephora species with the TP uplifts and associated climate changes during this time. Selection analyses revealed accelerated evolutionary rates of the mitochondrial protein-coding genes in the TP Gynaephora species, suggesting that they accumulated more nonsynonymous substitutions that may benefit their adaptation to high altitudes. Furthermore, signals of positive selection were detected in nad5 of two Gynaephora species with the highest altitude-distributions, indicating that this gene may contribute to Gynaephora's adaptation to divergent altitudes. This study adds to the understanding of the TP Gynaephora evolutionary relationships and suggests a link between mitogenome evolution and ecological adaptation to high-altitude environments in grassland caterpillars.
高山草地鳞翅目幼虫（Lepidoptera：Lymantriinae：Gynaephora）是青藏高原高寒草地最重要的害虫，已很好地适应了高海拔环境。为了进一步了解其进化历史及其对青藏高原的适应，我们新测定了青藏高原 7 种 Gynaephora 线粒体基因组。与单个基因相比，完整的线粒体基因组提供了最佳的系统发育信号，并获得了可靠的结果，支持了青藏高原 Gynaephora 物种的单系性和 Arctiinae+（Aganainae+Lymantriinae）的系统发育。在单个线粒体基因中发现了不一致的系统发育信号，没有一个基因能恢复与整个线粒体基因组相同的系统发育。我们通过 Shimodaira-Hasegawa 检验确定了 6 个表现最好的单基因，并发现 rrnS 与 cox1 或 cox3 的组合生成了与整个线粒体基因组相同的系统发育，这表明这三个基因在未来的 Gynaephora 进化研究中有系统发育潜力。青藏高原 Gynaephora 物种被估计在渐新世和第四纪在青藏高原上辐射，支持了青藏高原 Gynaephora 物种的多样化和物种形成与这一时期青藏高原的抬升和相关气候变化之间的联系。选择分析显示，青藏高原 Gynaephora 物种的线粒体蛋白质编码基因的进化速度加快，表明它们积累了更多可能有助于它们适应高海拔的非同义替换。此外，在两个分布海拔最高的 Gynaephora 物种的 nad5 中检测到了正选择信号，表明该基因可能有助于 Gynaephora 适应不同的海拔。本研究增加了对青藏高原 Gynaephora 进化关系的了解，并表明线粒体基因组进化与草地鳞翅目对高海拔环境的生态适应之间存在联系。
