Kraaijeveld-Smit F J L, Beebee T J C, Griffiths R A, Moore R D, Schley L
The Durrell Institute of Conservation and Ecology, University of Kent, Canterbury, Kent, CT2 7NS, UK.
Mol Ecol. 2005 Oct;14(11):3307-15. doi: 10.1111/j.1365-294X.2005.02614.x.
We investigated fine-scale genetic structuring in the rare and vulnerable Mallorcan midwife toad Alytes muletensis using eight polymorphic microsatellite markers. The current range of this amphibian is restricted to some 19 sites of which six are derived from reintroductions, all located in the mountain ranges of Mallorca. We sampled tadpoles from 14 pools covering 10 natural sites and two reintroduction sites for microsatellite DNA analyses. Relatively high levels of genetic variation were found in most pools (H(E) = 0.38-0.71, allelic richness = 2.6-6.2). Only at one pool has the population recently gone through a bottleneck. Dispersal between pools in different torrents does not occur whereas downstream dispersal between pools within the same torrent does happen at low frequencies. This occasional exchange of individuals does not lead to neighbouring pools in the same torrent being panmictic. This can be concluded because all F(ST) values (0.12-0.53) differ significantly from zero and STRUCTURE analyses identified neighbouring pools as separate populations. Furthermore, assignment and migration tests showed little exchange between neighbouring pools. If upstream locations or complete torrents go extinct, they are unlikely to be recolonized naturally. For conservation purposes, reintroductions of tadpoles to sites where local extinctions have occurred may therefore be advisable.
我们使用八个多态微卫星标记，对珍稀且濒危的马略卡产婆蟾（Alytes muletensis）进行了精细尺度的遗传结构研究。这种两栖动物目前的分布范围局限于约19个地点，其中六个是重新引入形成的，所有地点都位于马略卡岛的山脉中。我们从覆盖10个自然地点和两个重新引入地点的14个水塘中采集了蝌蚪，用于微卫星DNA分析。在大多数水塘中发现了相对较高水平的遗传变异（H(E)=0.38 - 0.71，等位基因丰富度 = 2.6 - 6.2）。只有一个水塘的种群最近经历了瓶颈效应。不同溪流中的水塘之间不会发生扩散，而同一溪流中不同水塘之间的下游扩散则以低频率发生。这种偶尔的个体交换并没有导致同一溪流中的相邻水塘成为随机交配群体。之所以能得出这个结论，是因为所有的F(ST)值（0.12 - 0.53）都显著不同于零，并且STRUCTURE分析将相邻水塘识别为独立的种群。此外，分配和迁移测试表明相邻水塘之间几乎没有交换。如果上游地点或整个溪流灭绝，它们不太可能自然重新定殖。因此，出于保护目的，将蝌蚪重新引入当地已经灭绝的地点可能是可取的。
