水杉个体DNA身份认证与管理单元确定

Reducing the rate of biodiversity loss and averting dangerous biodiversity change are international goals, which were reasserted by the Aichi Targets by Parties to Convention on Biological Diversity (CBD). The CBD states that participating nations should implement a system to identify and monitoring components of biological diversity. However, most biodiversity monitoring was only operated on species diversity, while the changes in genetic diversity are still poorly understood. It is therefore necessary to carry out genetic monitoring, a powerful measure to detect genetic changes, particular for endangered species, because the loss of genetic diversity also threatens the maintenance of species, causing biodiversity loss. In this study, we focus on the genetic diversity of Metasequoia glyptostroboides, a severely endangered species, and will genotype all the wild individuals of this species using microsatellite (SSR) molecular markers, to reveal its entire background for the long-term genetic monitoring. Then we will identify the prior conservation individuals owning rare alleles, and will determine the Management Units (MUs) for the conservation by analyzing the population genetic divergences that lower significantly than the predefined threshold value. Finally, we will test the effects of landscape pattern on spatial genetic structure of M. glyptostroboides, and try to find out the factors that are likely to cause the loss of genetic diversity. This study will provide not only critical information for improving the conservation strategy of M. glyptostroboides, but also an ideal background for further testing and developing the ecological and evolutionary theories concerning biodiversity conservation.

生物多样性监测是全球保护生物多样性的重要途径，旨在从整体上对生物多样性变化开展长期的跟踪和研究。但目前监测对象大多着重于物种多样性，而缺乏对遗传多样性的监测。遗传多样性减少可降低物种的进化潜力，影响繁殖适合度，增大灭绝风险，进而造成生物多样性丧失，因此开展物种的定期遗传监测是必要而迫切的。本研究针对我国珍稀濒危植物的旗舰种水杉(Metasequoia glyptostroboides)现存全部5000余株野生个体，通过微卫星分子标记确定所有个体的基因型，为水杉遗传多样性长期监测提供本底值。在此基础上，进行景观遗传学研究揭示影响种群遗传变异空间分布格局的因素。最后，通过检测稀有等位基因以确定重点保护个体；分析种群间遗传分化及迁移率，并结合景观遗传学分析确定保护管理单元(MUs)。本研究将为优化水杉保护策略提供指导，为甄别重点保护个体和保护管理单元提供范例，也为生物多样性保护提供参考价值。

遗传多样性监测是全球生物多样性保护的重要方面，可从进化潜力方面对种群变化开展长期的跟踪和预测，同时，对其进行种群遗传学分析为探讨物种的生态和演化规律提供基础。本项目针对我国珍稀濒危植物的旗舰种水杉(Metasequoia glyptostroboides)现存的全部野生5600多株个体，采用12对微卫星分子标记对所有个体进行基因分型，为水杉种群遗传多样性的长期监测提供本底值。根据基因分型信息鉴定每个个体独特的基因型，可进行遗传分型的个体比例达到99.79%，几乎所有现存个体都被标记上独特的DNA标签，建立了濒危种水杉的遗传信息资源库。在此基础上进行种群的景观遗传学分析，对所有个体基因型遗传聚类可划分为2个遗传种群，分别处于分布区的东部和西部；通过遗传多样性分析表明，西部种群的平均等位基因数、等位基因丰富度和期望杂合度均高于东部种群；应用空间自相关和阻力隔离模型探讨影响遗传变异空间分布的景观特征，揭示多种自然因素和人为因素影响水杉种群的空间遗传分布。最后，通过检测稀有等位基因和常见等位基因，结合个体的地理分布格局，确定了124株为重点保护个体和水杉的种质资源，并将所有水杉个体划分为6个管理单元用于保护实践。本研究为水杉种群提供了“全个体组”的遗传本底数据，揭示了种群空间遗传格局及其影响因素，甄别了重点保护个体和种质资源，提出了水杉保护的管理单元，为优化水杉保护策略提供指导，为濒危植物和极小种群物种的保护提供范例，为生物多样性保护提供参考价值。