| Dispersal is an important process that influences population regeneration, community dynamics as well as ecosystem functioning. The historical dispersal pattern and its key influential factors can be inferred by contemporary genetic structure of populations. Fig is a key group in tropical and subtropical ecosystems. Figs and their pollinating wasps are one of the most tightly integrated pollination mutualisms known, the present study analyzed genetic structure of Ficus pumila and inferred the potential dispersal pattern, which will help to understand coevolution relationship of F. pumila and its pollinating wasps.Polymorphic microsatellite loci (SSR) were isolated and characterized for F. pumila, and eight of them were applied to examine genetic structure of69F. pumila populations in eastern China. The main results are as follows.1) The software STRUCTURE divided all populations into2clusters (C and E clusters), which was roughly separated by the NanLing Mts and DaiYun Mts. The LuoXiao Mts further could separate cluster C into2groups. Moderate genetic differentiation was found among populations (F'ST=0.389), and there was an isolation-by-distance in this species. Such a pattern suggested that geographic barriers might have limited gene flow. Compared with speciation and allopatric distribution in its pollinators, F. pumila was less differentiated, indicating a difference in differentiation rate in this mutualistic system.2) There was a positive relationship between genetic diversity and latitude of populations, not consistent with the central-peripheral hypothesis. The pattern of genetic diversity in F. pumila populations might be the result of postglacial colonization from southern refugia. Combined with cpDNA data, the possible colonization routes of postglacial dispersal were inferred. |
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