濒危长江江豚的近交避免与配偶选择机制研究

The Yangtze finless porpoise (YFP, Neophocaena asiaeorientalis asiaeorientalis) is the sole freshwater finless porpoise population endemic to China, which is currently critically endangered. Both ecological surveys and conservation genetics studies indicate that the YFP wild population living in the Yangtze main stream is becoming a small and fragmented population, meanwhile the ex situ conserved population in the Tian-e-Zhou Oxbow shows high risk of inbreeding. And thus, scientific research and effective conservation measures are urgently necessary to save this population. Revealing the potential mechanisms of inbreeding avoidance and mate choice will greatly enhance the conservation and management of a critically endangered species or population. In this proposal, we will focus on the ex situ conserved YFP population living in the Tian-e-Zhou National Natural Reserve and the wild population living in the Poyang Lake. Comparative and systematic studies will be carried out on both populations combining molecular ecology and behavior ecology methods, to investigate their social structure, dispersal pattern, breeding rule and mate choice. We aim to reveal the potential mechanisms of inbreeding avoidance and mate choice in the YFP and how it works. And also we will try to reveal the molecular and genetic bases of these inbreeding avoidance mechanisms. Findings obtained from this project will be instructively significant to increase the reproductive success rate of the ex situ conserved and captive YFP populations, and to enhance their breeding management.

长江江豚是我国特有的江豚淡水种群，目前已处于极度濒危状况。近年来开展的种群生态学调查和保护遗传学研究表明，其自然种群正在逐渐成为破碎化小种群，而迁地保护种群则存在较高的近交风险，因而亟待加强研究和保护。开展近交避免与配偶选择机制研究对于濒危物种的保护和管理具有重要指导意义。本项目以天鹅洲迁地保护江豚种群和鄱阳湖自然种群为研究对象，拟结合分子生态学和行为生态学手段，系统地研究并比较他们的社群结构、扩散模式、繁殖规律及配偶选择策略，探索长江江豚是否存在近交避免机制，以及如何通过个体扩散和配偶选择策略来实现近交避免。本研究还将进一步揭示其可能存在的基于MHC基因的配偶选择的分子机制。本项目的开展对于提高迁地保护和人工豢养江豚种群的繁殖成功率以及加强种群繁殖管理具有重要指导意义。

长江江豚是我国特有的江豚淡水种群，目前已处于极度濒危状况。近年来开展的种群生态学调查和保护遗传学研究表明，其自然种群正在逐渐成为破碎化小种群，而迁地保护种群则存在较高的近交风险，亟待加强研究和保护。开展近交避免与配偶选择机制研究对于濒危物种的保护和管理具有重要指导意义。本项目以天鹅洲迁地保护江豚种群和鄱阳湖自然种群为研究对象，结合分子生态学和行为生态学手段，系统地研究并比较他们的社群结构、扩散模式、繁殖规律及配偶选择策略，探索长江江豚是否存在近交避免机制，以及如何通过个体扩散和配偶选择策略来实现近交避免。本项目得到的主要结果和结论如下：证实天鹅洲迁地保护江豚种群具有较高近交风险，亟待加强种群管理；成功为天鹅洲种群构建接近完整的遗传谱系，首次揭示该物种的一些重要繁殖规律；证实该种群存在雌性主导的配偶选择机制，主要通过亚成年雄性扩散来避免近亲繁殖，并且可能具备基于声通讯的个体识别能力从而避免近亲繁殖；长江江豚可能不存在基于MHC Ⅱ类基因型和微卫星遗传杂合度的配偶选择机制，其分子机制依然有待后续研究证实。本项目的实施对于提高迁地保护江豚种群的繁殖成功率，加强种群管理具有重要指导意义。