Genetic structure and connectedness of Southern Ocean pycnogonids (Chelicerata: Pycnogonida) in a changing environment

在大洋盆地尺度上，南大洋锥虫数量丰富，种类多样，具有高度地方性。尽管近年来在海洋南极无脊椎动物的分子进化研究方面做了一些努力，但对巨齿纲的研究仍然很少。因此，关于它们的进化史的许多问题仍然存在，而常见的动物地理学假设，例如环极分布的概念，大部分仍未得到验证。提出的项目的目的是分析这种报告的环极分布的pynogonids的遗传结构。测序核和线粒体基因，我们首先要测试报告的环极分布是否正确，或者仅仅是由于隐藏物种的存在而人为的。其次，对于已验证的物种，我们的目标是利用新开发的微卫星和创新的生物信息学方法，结合南大洋的物理和生物海洋学信息，调查种群间基因流动的数量和方向。在第三步中，使用相同的DNA标记，我们想测试南极大陆架上的浅水物种是否比垂直分布范围广泛的物种遭受了更多的冰川事件，因为这些物种可能逃到了深海。由于气候的快速变化，南大洋正在发生和即将发生的环境变化，我们对南极螺的种内和种间遗传多样性的分析为监测南极生物群对变化条件的响应提供了重要的基线研究。

Southern Ocean pycnogonids are abundant, diverse and highly endemic on an ocean basin scale. Despite some efforts in molecular evolutionary research on marine Antarctic invertebrates in recent years, the pycnogonids remain mostly unstudied. Hence, many questions concerning their evolutionary history remain and common zoogeographic hypotheses, e.g. the concept of circumpolar distribution, remain mostly untested. The aim of the proposed project is to analyse the genetic structure of pycnogonids with such a reported circumpolar distribution. Sequencing nuclear and mitochondrial genes, we first want to test whether the reported circumpolar distribution holds true or is just artifactual due to the presence of cryptic species. Second, for verified species, we aim at investigating the amount and direction of gene flow among populations using newly developed microsatellites and innovative bioinformatic approaches together with physical and biologcial oceanographic information on the Southern Ocean. In a third step, using the same DNA markers, we want to test whether shallow-water species on the Antarctic shelf have suffered more from past glaciation events compared to species with broad vertical distribution ranges since these may have escaped to the deep sea. In view of ongoing and upcoming environmental changes in the Southern Ocean as a result of a fast changing climate, our analyses of today’s intra- and interspecific genetic diversity of Antarctic Pycnogonida represent important baseline research for monitoring the response of Antarctic biota to changing conditions.