Prasankok Pongpun, Ota Hidetoshi, Toda Mamoru, Panha Somsak
Animal Systematic Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand.
Zoolog Sci. 2007 Feb;24(2):189-97. doi: 10.2108/zsj.24.189.
We examined allozyme variation in two camaenid tree snails, Amphidromus atricallosus and A. inversus, across two principal regions of Thailand and from Singapore, plus for A. inversus, one site in peninsular Malaysia. Using horizontal starch gel electrophoresis, 13 allozyme loci (11 polymorphic) were screened for A. atricallosus and 18 (5 polymorphic) for A. inversus. Heterozygosity was higher in A. atricallosus (Hexp=0.018-0.201, mean=0.085) than in A. inversus (Hexp=0-0.023, mean= 0.002). Genetic heterogeneity among samples was higher in A. inversus (Fst=0.965) than in A. atricallosus (Fst=0.781). Within A. atricallosus, populations were more differentiated in southern Thailand (Fst=0.551) than in eastern Thailand (Fst=0.144). The high Fst and low Hexp in populations of A. inversus suggest that this species is likely to have experienced a series of strong bottlenecks, perhaps occurring chiefly on offshore continental-shelf islands. The low Fst values of A. atricallosus in eastern Thailand suggest frequent gene flows among populations in this region. The southern and eastern samples of A. atricallosus exhibited fixed allele differences at four loci and great genetic distance (Nei's D=0.485-0.946), suggesting that these two samples may actually represent, or else be evolving into, separate species.
我们研究了两种山蜗牛科树蜗牛，即黑带环口螺（Amphidromus atricallosus）和反向环口螺（A. inversus）在泰国两个主要地区以及新加坡的等位酶变异情况，对于反向环口螺，还研究了马来西亚半岛的一个地点。使用水平淀粉凝胶电泳，对黑带环口螺筛选了13个等位酶位点（11个多态性位点），对反向环口螺筛选了18个（5个多态性位点）。黑带环口螺的杂合度（Hexp = 0.018 - 0.201，平均值 = 0.085）高于反向环口螺（Hexp = 0 - 0.023，平均值 = 0.002）。反向环口螺样本间的遗传异质性（Fst = 0.965）高于黑带环口螺（Fst = 0.7-eight1）。在黑带环口螺中，泰国南部的种群分化程度（Fst = 0.551）高于泰国东部（Fst = 0.144）。反向环口螺种群中高Fst和低Hexp表明该物种可能经历了一系列强烈的瓶颈效应，可能主要发生在近海大陆架岛屿上。泰国东部黑带环口螺的低Fst值表明该地区种群间基因流动频繁。黑带环口螺的南部和东部样本在四个位点表现出固定等位基因差异和较大的遗传距离（Nei氏D = 0.485 - 0.946），这表明这两个样本可能实际上代表不同物种，或者正在进化为不同物种。
