Hauswaldt J Susanne, Glenn Travis C
Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA.
Mol Ecol. 2005 Mar;14(3):723-32. doi: 10.1111/j.1365-294X.2005.02451.x.
We examined the population genetic structure of the diamondback terrapins (Malaclemys terrapin), within and among estuaries. Based on mark-recapture studies, these estuarine turtles have high site fidelity that is likely to make them vulnerable to local extinctions. We tested if observed site fidelity of adults would be reflected in intraestuarine population genetic structure of six highly polymorphic microsatellite loci (five tetranucleotide and one dinucleotide). No evidence was found for population structuring within the Charleston estuary nor among three different estuaries in South Carolina. We then examined four other terrapin populations from North Carolina to New York, as well as from the Florida Keys and from Texas. With increasing geographical distance, genetic differentiation increased from South Carolina through New York, but overall values were low. The dinucleotide locus contributed significantly more to the genetic differentiation of some population comparisons than any of the other loci. Interestingly, terrapins from South Carolina to New York were much more genetically similar to those from Texas (rho = 0.154) than to those from Florida (rho = 0.357). We attribute this pattern to extensive translocations of terrapins during the early 20th century to replenish diminished populations and to provide turtle farms with stocks. Terrapins collected in Texas were especially sought for shipment to the northeastern US because of their larger size. Our study indicates no population structure within or among adjacent estuaries. Thus, the mark-recapture information from adult and subadult feeding locations is a poor predictor of population genetic structure. Additionally, it appears that past human activities may have drastically altered the genetics of current populations. Finally, our data suggest that translocation of eggs or head starting of terrapins within estuaries or among adjacent estuaries is acceptable from a genetic standpoint.
我们研究了盐沼龟（菱斑龟，学名：Malaclemys terrapin）在河口内部和不同河口之间的种群遗传结构。基于标记重捕研究，这些河口龟具有很高的场地忠诚度，这可能使它们容易遭受局部灭绝。我们测试了成年龟观察到的场地忠诚度是否会反映在六个高度多态性微卫星位点（五个四核苷酸和一个二核苷酸）的河口内种群遗传结构中。在查尔斯顿河口内部或南卡罗来纳州的三个不同河口之间均未发现种群结构的证据。然后，我们研究了从北卡罗来纳州到纽约以及佛罗里达群岛和得克萨斯州的其他四个龟种群。随着地理距离的增加，从南卡罗来纳州到纽约，遗传分化增加，但总体值较低。在某些种群比较中，二核苷酸位点对遗传分化的贡献明显大于任何其他位点。有趣的是，从南卡罗来纳州到纽约的龟在遗传上与来自得克萨斯州的龟（rho = 0.154）比与来自佛罗里达州的龟（rho = 0.357）更为相似。我们将这种模式归因于20世纪初龟的广泛迁移，以补充减少的种群并为海龟养殖场提供种源。由于得克萨斯州收集的龟体型较大，因此特别被运往美国东北部。我们的研究表明，相邻河口内部或之间没有种群结构。因此，来自成年和亚成年龟觅食地点的标记重捕信息并不能很好地预测种群遗传结构。此外，过去的人类活动似乎可能极大地改变了当前种群的基因。最后，我们的数据表明，从遗传角度来看，在河口内或相邻河口之间转移龟卵或进行龟的提前孵化是可以接受的。
