Zheng Zeyu, Li Ying, Li Minjie, Li Guiting, Du Xin, Hongyin Hu, Yin Mou, Lu Zhiqiang, Zhang Xu, Shrestha Nawal, Liu Jianquan, Yang Yongzhi
State Key Laboratory of Grassland Agro-Ecosystem, Institute of Innovation Ecology and School of Life Sciences, Lanzhou University, Lanzhou, China.
CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, China.
Front Plant Sci. 2021 Feb 10;12:581704. doi: 10.3389/fpls.2021.581704. eCollection 2021.
Speciation is the key evolutionary process for generating biological diversity and has a central place in evolutionary and ecological research. How species diverge and adapt to different habitats is one of the most exciting areas in speciation studies. Here, we sequenced 55 individuals from three closely related species in the genus : , , and to understand the strength and direction of gene flow and selection during the speciation process. We found low genetic diversity in , which reflects its extremely small effective population size. The speciation analysis between and revealed that both species diverged ∼1.2 Mya with bidirectional gene flow. A total of 291 highly diverged genes, 223 copy number variants genes, and 269 positive selected genes were recovered from the two species. Genes associated with the diverged and positively selected regions were mainly involved in thermoregulation, plant development, and response to stress, which included adaptations to their habitats. We also found a great population decline and a low genetic divergence of , which suggests that this species is extremely vulnerable. We believe that the current diversification and adaption study and the important genomic resource sequenced herein will facilitate the speciation studies and serve as an important methodological reference for future research.
物种形成是产生生物多样性的关键进化过程，在进化和生态研究中占据核心地位。物种如何分化并适应不同栖息地是物种形成研究中最令人兴奋的领域之一。在此，我们对来自该属三个近缘物种（ 、 和 ）的55个个体进行了测序，以了解物种形成过程中基因流动和选择的强度与方向。我们发现 中的遗传多样性较低，这反映了其极小的有效种群规模。 与 之间的物种形成分析表明，这两个物种在约120万年前发生分化，存在双向基因流动。从这两个物种中总共鉴定出291个高度分化基因、223个拷贝数变异基因和269个正选择基因。与分化和正选择区域相关的基因主要参与体温调节、植物发育和应激反应，其中包括对其栖息地的适应。我们还发现 种群大幅减少且遗传分化较低，这表明该物种极其脆弱。我们相信，当前的多样化和适应性研究以及本文测序的重要基因组资源将促进物种形成研究，并为未来研究提供重要的方法参考。
