Xiao Siyue, Ji Yunheng, Liu Jian, Gong Xun
Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, No. 132 Lanhei RD, Panlong District, Kunming, Yunnan province, 650201, China.
University of Chinese Academy of Sciences, No. 19A, Yuquan Road, Shijingshan District, Beijing, 100049, China.
Plant Divers. 2019 Oct 16;42(1):7-18. doi: 10.1016/j.pld.2019.10.001. eCollection 2020 Feb.
L. Zhou & S. Y. Yang (Cycadaceae) is an endangered gymnosperm species endemic to the dry-hot valley of the Jinsha River basin in southwest China. Although the wild population from Panzhihua Cycad Natural Reserve is well protected and its genetic diversity has been well assessed, the genetic characteristics of populations outside the nature reserve, which face larger risks of extinction, remain unknown. Furthermore, the population genetics and historical dynamics of this endemic and endangered species have not been examined across its entire range. In this study, to analyze the genetic diversity, phylogeographical structure and demographic history of from all its seven known locations, we sequenced and compared molecular data from chloroplastic DNA (A-H, M-D, and S-G), single-copy nuclear genes (, , , and ) from 61 individuals, as well as 11 nuclear microsatellite loci (SSR) from 102 individuals. We found relatively high genetic diversity within populations and high genetic differentiation among populations of , which is consistent with the patterns of other Asian inland cycads. Although no significant phylogeographical structure was detected, we found that small and unprotected populations possess higher genetic diversity and more unique haplotypes, which revises our understanding of diversity within this species and deserves due attention. Analysis of demographic dynamics suggest that human activity might be the key threat to . Based on the genetic characterization of , we propose several practical guidelines for the conservation of this species, especially for the populations with small sizes.
周莉和杨世勇（苏铁科）是一种濒危裸子植物，特产于中国西南部金沙江流域的干热河谷。尽管攀枝花苏铁自然保护区的野生种群得到了很好的保护，其遗传多样性也得到了很好的评估，但自然保护区外面临更大灭绝风险的种群的遗传特征仍然未知。此外，这种特有濒危物种在其整个分布范围内的种群遗传学和历史动态尚未得到研究。在本研究中，为了分析来自其所有七个已知地点的[物种名称未明确]的遗传多样性、系统地理学结构和种群历史，我们对61个个体的叶绿体DNA（A-H、M-D和S-G）、单拷贝核基因（[基因名称未明确]）以及102个个体的11个核微卫星位点（SSR）的分子数据进行了测序和比较。我们发现[物种名称未明确]种群内遗传多样性相对较高，种群间遗传分化程度较高，这与其他亚洲内陆苏铁的模式一致。尽管未检测到明显的系统地理学结构，但我们发现小型且未受保护的种群具有更高的遗传多样性和更多独特的单倍型，这修正了我们对该物种内多样性的认识，值得给予应有的关注。种群动态分析表明，人类活动可能是[物种名称未明确]面临的关键威胁。基于[物种名称未明确]的遗传特征，我们提出了一些保护该物种的实用指导方针，特别是针对小型种群。
