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Molecular Ecology:中国科学家在岛屿蛙类遗传多样性丧失方面取得新进展

  1. 岛屿
  2. 蛙类
  3. 遗传多样性

来源:生物谷 2014-02-14 09:22

2014年2月中科院动物所李义明研究组在 Molecular Ecology上发表了题为《Population size and time since island isolation determine genetic diversity loss in insular frog populations》的论文。结果显示,岛屿种群的遗传多样性小于大陆种群;岛屿间以及岛屿与大陆间不存在基因流;各岛屿种群及大陆种群间已出现明显的遗传分化;各岛屿种群及大陆种群均未显示出明显的近期遗传瓶颈现象;单元回归分析表明,岛屿种群的遗传多样性与其面积和种群大小呈正相关,与岛屿隔离时间呈负相关。而层次划分分析显示,只有岛屿种群大小和岛屿隔离时间是影响岛屿种群遗传多样性的主要因素。降低的岛屿种群遗传多样性和遗传分化是由于全新世(近10000年)海平面上升后伴随着岛屿隔离而产生的随机遗传漂变引发的。这些结果与有限种群的中性理论预测一致。该研究强调岛屿隔离时间和种群大小在理解破碎种群遗传多样性丧失和遗传分化方面的重要性。

遗传多样性丧失会降低种群的适合度和进化潜力,使种群对绝灭非常敏感。而长期隔离的小种群面临着巨大的遗传多样性丧失风险。确定它们的遗传多样性丢失原因对制定保护策略至关重要。陆桥岛是研究种群遗传和进化以及破碎种群遗传多样性丧失的天然理想模型系统。亚洲岛屿众多,但有关岛屿动物种群的遗传多样性研究却很少。多样性与空间生态学研究组探讨了我国最大的陆桥群岛-舟山群岛上黑斑蛙(Pelophylax nigromaculatus)种群的遗传多样性和遗传分化格局。他们研究了24个岛屿种群,以相邻的宁波大陆三个地点的种群为对照,利用9个微卫星位点量化岛屿面积、岛屿种群大小、岛屿隔离时间、离大岛的距离和离大陆的距离对岛屿种群遗传多样性和遗传分化的影响。(生物谷Bioon.com)

生物谷推荐的英文摘要

Molecular Ecology    DOI: 10.1111/mec.12634

Population size and time since island isolation determine genetic diversity loss in insular frog populations

Supen Wang, Wei Zhu, Xu Gao, Xianping Li, Shaofei Yan, Xuan Liu, Ji Yang, Zengxiang Gao, Yiming Li

Understanding the factors that contribute to loss of genetic diversity in fragmented populations is crucial for conservation measurements. Land-bridge archipelagoes offer ideal model systems for identifying the long-term effects of these factors on genetic variations in wild populations. In this study, we used nine microsatellite markers to quantify genetic diversity and differentiation of 810 pond frogs (Pelophylax nigromaculatus) from 24 islands of the Zhoushan Archipelago and three sites on nearby mainland China and estimated the effects of the island area, population size, time since island isolation, distance to the mainland and distance to the nearest larger island on reduced genetic diversity of insular populations. The mainland populations displayed higher genetic diversity than insular populations. Genetic differentiations and no obvious gene flow were detected among the frog populations on the islands. Hierarchical partitioning analysis showed that only time since island isolation (square-root-transformed) and population size (log-transformed) significantly contributed to insular genetic diversity. These results suggest that decreased genetic diversity and genetic differentiations among insular populations may have been caused by random genetic drift following isolation by rising sea levels during the Holocene. The results provide strong evidence for a relationship between retained genetic diversity and population size and time since island isolation for pond frogs on the islands, consistent with the prediction of the neutral theory for finite populations. Our study highlights the importance of the size and estimated isolation time of populations in understanding the mechanisms of genetic diversity loss and differentiation in fragmented wild populations.

 

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