Population structure and historical demography of Dipteronia dyeriana (Sapindaceae), an extremely narrow palaeoendemic plant from China: implications for conservation in a biodiversity hot spot
Population structure and historical demography of Dipteronia dyeriana (Sapindaceae), an extremely narrow palaeoendemic plant from China: implications for conservation in a biodiversity hot spot
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中国极窄的古特有植物双翅目（无患子科）的种群结构和历史人口统计：对生物多样性热点地区保护的影响
DOI：
10.1038/hdy.2017.19
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发表时间：
2017-08-01
期刊：
影响因子：
3.8
通讯作者：
Qiu, Y. X.
中科院分区：
文献类型：
--
作者：
Chen, C.;Lu, R. S.;Qiu, Y. X.
推断过去的人口统计是进化和保护生物学的一个中心问题。然而，有时很难理清它们在塑造濒危物种遗传变异的当前模式中的当代与历史过程中的作用。在这项研究中，我们同时使用叶绿体微卫星（cpSSR）位点和核微卫星（nSSR）位点，以评估的遗传分化水平，遗传有效人口规模，当代/历史水平的基因流和人口统计历史的5个种群采样的范围内的Dipteronia dyeriana，从中国西南部的濒危古特有种。我们发现D. dyeriana具有中等遗传多样性和高度近交的混合模式。贝叶斯聚类将D. dyeriana群体分为两个nSSR遗传簇。基于凝聚的近似贝叶斯计算分析表明，西部和东部的D。dyeriana可能自末次盛冰期开始就在中国南方长期避难，而末次盛冰期开始时日益寒冷和干旱的气候可能促进了D. dyeriana内避难所。在分化之后，西部群保持了相对稳定的有效种群规模，而东部群在全新世经历了500倍的种群扩张。虽然没有明确的人类活动的遗传多样性损失的建议，最近的栖息地破碎化已导致人口的连接性降低，并增加了遗传分化的持续遗传漂变在孤立的人群，可能是由于人口规模在最近十几年。最后，我们讨论了这些结果对保护政策的影响。
Inferring past demography is a central question in evolutionary and conservation biology. It is, however, sometimes challenging to disentangle their roles of contemporary versus historical processes in shaping the current patterns of genetic variation in endangered species. In this study, we used both chloroplast microsatellite (cpSSR) loci and nuclear microsatellite (nSSR) loci to assess the levels of genetic differentiation, genetic effective population size, contemporary/historical levels of gene flow and demographic history for five populations sampled across the range of Dipteronia dyeriana, an endangered palaeoendemism from Southwestern China. We found that D. dyeriana had a mixed pattern of moderate genetic diversity and high inbreeding. Bayesian clustering divided D. dyeriana populations into two nSSR genetic clusters. Coalescent-based approximate Bayesian computation analyses suggest the western and eastern groups of D. dyeriana likely persisted in a long-term refuge in Southern China since the beginning of the last glacial period, whereas increasingly colder and arid climates at the onset of the last glacial maximum might have fostered the fragmentation of D. dyeriana within refugia. Following their divergence, the western group kept relatively stable effective population size, whereas the eastern group had experienced 500-fold population expansion during the Holocene. Although clear loss of genetic diversity by human activities was not suggested, recent habitat fragmentation has led to a reduction of population connectivity and increased genetic differentiation by ongoing genetic drift in isolated populations, possibly owing to decreased population size in recent dozen years. Finally, we discussed the implications of these results on conservation policies.