Data from: Biogeography in a continental island: population structure of the relict endemic centipede Craterostigmus tasmanianus (Chilopoda, Craterostigmomorpha) in Tasmania using 16S rRNA and COI

We used 16S ribosomal RNA (rRNA) and cytochrome c oxidase subunit I (COI) sequence data to investigate the population structure in the centipede Craterostigmus tasmanianus Pocock, 1902 (Chilopoda: Craterostigmomorpha: Craterostigmidae) and to look for possible barriers to gene flow on the island of Tasmania, where C. tasmanianus is a widespread endemic. We first confirmed a molecular diagnostic character in 28S rRNA separating Tasmanian Craterostigmus from its sister species Craterostigmus crabilli (Edgecombe and Giribet 2008) in New Zealand and found no shared polymorphism in this marker for the 2 species. In Tasmania, analysis of molecular variance analysis showed little variation at the 16S rRNA and COI loci within populations (6% and 13%, respectively), but substantial variation (56% and 48%, respectively) among populations divided geographically into groups. We found no clear evidence of isolation by distance using a Mantel test. Bayesian clustering and gene network analysis both group the C. tasmanianus populations in patterns which are broadly concordant with previously known biogeographical divisions within Tasmania, but we did not find that genetic distance varied in a simple way across cluster boundaries. The coarse-scale geographical sampling on which this study was based should be followed in the future by sampling at a finer spatial scale and to investigate genetic structure within clusters and across cluster boundaries.

本研究采用16S核糖体RNA（16S ribosomal RNA, rRNA）与细胞色素C氧化酶亚基I（cytochrome c oxidase subunit I, COI）序列数据，对塔斯马尼亚蜈蚣（Craterostigmus tasmanianus Pocock, 1902，唇足纲（Chilopoda）：Craterostigmomorpha目：Craterostigmidae科）的种群结构展开探究，并旨在探寻该物种在塔斯马尼亚岛上的基因流潜在障碍——该物种是塔斯马尼亚广泛分布的特有种。本研究首先在28S rRNA中确认了一项分子鉴定特征，可将塔斯马尼亚的Craterostigmus属物种与其新西兰姊妹种（sister species）Craterostigmus crabilli（Edgecombe与Giribet, 2008）区分开来，且二者在该分子标记（marker）中未发现共享多态性位点。针对塔斯马尼亚种群的分子方差分析（analysis of molecular variance）结果显示：16S rRNA与COI基因座（locus，复数loci）在种群内部的变异占比分别仅为6%与13%，而在按地理分组的种群间，变异占比则高达56%与48%。通过曼特尔检验（Mantel test）未发现显著的距离隔离（isolation by distance）效应。贝叶斯聚类（Bayesian clustering）与基因网络分析均显示，C. tasmanianus的种群分组模式与塔斯马尼亚岛内此前已探明的生物地理分区大体吻合，但未发现遗传距离（genetic distance）在聚类边界处呈现简单的变化规律。本研究基于粗尺度的地理采样方案，未来应开展更精细的空间尺度采样，以探究聚类内部及聚类边界间的遗传结构。