Open-ocean environments provide few obvious barriers to the dispersal of marine organisms. Major currents and/or environmental gradients potentially impede gene flow. One system hypothesized to form an open-ocean dispersal barrier is the Antarctic Polar Front, an area characterized by marked temperature change, deep water, and the high-flow Antarctic Circumpolar current. Despite these potential isolating factors, several invertebrate species occur in both regions, including the broadcast-spawning nemertean worm Parborlasia corrugatus. To empirically test for the presence of an open-ocean dispersal barrier, we sampled P. corrugatus and other nemerteans from southern South America, Antarctica, and the sub-Antarctic islands. Diversity was assessed by analyzing mitochondrial 16S rRNA and cytochrome c oxidase subunit I sequence data with Bayesian inference and TCS haplotype network analysis. Appropriate neutrality tests were also employed. Although our results indicate a single well-mixed lineage in Antarctica and the sub-Antarctic, no evidence for recent gene flow was detected between this population and South American P. corrugatus. Thus, even though P. corrugatus can disperse over large geographical distances, physical oceanographic barriers (i.e. Antarctic Polar Front and Antarctic Circumpolar Current) between continents have likely restricted dispersal over evolutionary time. Genetic distances and haplotype network analysis between South American and Antarctic/ sub-Antarctic P. corrugatus suggest that these two populations are possibly two cryptic species.
此資源出現紀錄的資料已發佈為達爾文核心集檔案（DwC-A），其以一或多組資料表構成分享生物多樣性資料的標準格式。 核心資料表包含 104 筆紀錄。
Thornhill,D.J., Mahon,A.R., Norenburg,J.L. and Halanych,K.M. Molecular Ecology (2008) 17, 5104-5218
此資料的發布者及權利單位為 SCAR - AntOBIS。 This work is licensed under a Creative Commons Attribution (CC-BY) 4.0 License.
|Online dataset||http://www.iobis.org/mapper/?dataset=1605 UTF-8 Plain Text|
|Metadata||http://www.vliz.be/imis/imis.php?module=dataset&dasid=2002 UTF-8 XMl|
|界定座標範圍||緯度南界 經度西界 [-70, -70], 緯度北界 經度東界 [-50, 5]|
|Phylum||Nemertina [Ribbon worms]|
marine, harvested by iOBIS