Amphibian and Reptile Diversity Research Center, Department of Biology, University of Texas at Arlington, Arlington, TX 76010, USA.
Integr Comp Biol. 2012 Aug;52(2):321-30. doi: 10.1093/icb/ics088. Epub 2012 Jun 1.
The yellow-bellied sea snake, Pelamis platurus (Elapidae, Hydrophiinae), has the largest distribution of any snake species, and patterns related to its distribution and regional color variation suggest there is population structuring in this species. Here, we use mitochondrial (ND4, Cyt-b) and nuclear (RAG-1) DNA to (1) test whether genetic variation is associated with local variation in color pattern, and (2) assess whether large-scale patterns of genetic variation are correlated with geographic distribution across the Pacific Ocean. We found low levels of genetic variation and shallow population structure that are correlated with local variation in color pattern and with geographic distribution. The low levels of genetic divergence indicate a relatively high rate of gene flow throughout the Pacific region and/or a recent expansion of range, both of which could be attributable to the passive drifting of these snakes on oceanic surface currents. The mtDNA data conform closely to a model of past exponential population growth, and this may have been associated with the species' large eastward and westward expansion of range. The pattern of low nucleotide and high haplotype diversity suggests that this population growth occurred in the relatively recent past. Data from drifting buoys can potentially act as informative models for predicting patterns of drifting in Pelamis and for generating additional testable hypotheses relating to its population structure and biogeography. Future studies should employ nuclear microsatellite markers to investigate population structure in this species at a finer scale. The exploitation of oceanic currents as a novel and highly efficient dispersal mechanism has likely facilitated gene flow throughout the Pacific Ocean in this uniquely pelagic species of sea snake, resulting in a distribution spanning over half of the earth's circumference.
黄腹海蛇（Pelamis platurus）（眼镜蛇科，海蛇科）是分布范围最广的蛇种，其分布模式及区域性颜色变化表明该物种存在种群结构。在这里，我们使用线粒体（ND4、Cyt-b）和核（RAG-1）DNA 来：（1）测试遗传变异是否与颜色图案的局部变化有关，（2）评估遗传变异的大尺度模式是否与太平洋跨地区的地理分布相关。我们发现遗传变异水平较低，种群结构较浅，与颜色图案的局部变化以及地理分布相关。遗传分歧程度较低表明，太平洋地区的基因流动相对较高，或者是范围的近期扩张，这两者都可能归因于这些蛇在海洋表面流上的被动漂移。mtDNA 数据与过去种群指数增长的模型非常吻合，这可能与该物种向东和向西的大范围扩张有关。低核苷酸和高单倍型多样性的模式表明，这种种群增长发生在相对较近的过去。漂流浮标上的数据可以作为预测 Pelamis 漂流模式的信息模型，并生成与其种群结构和生物地理学相关的额外可测试假设。未来的研究应该使用核微卫星标记来更精细地研究该物种的种群结构。利用海洋洋流作为一种新颖而高效的扩散机制，可能促进了太平洋地区的基因流动，使这种独特的海洋海蛇分布范围跨越了地球周长的一半以上。
