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

南大洋海盆中的海鞘数量丰富、种类繁多、具有高度的特有性。尽管近年来在南极海洋无脊椎动物的分子进化研究方面做了一些努力，但大部分的研究仍然是空白。因此，许多关于它们进化历史的问题仍然存在，常见的动物地理学假设，例如环极分布的概念，仍然大多未经验证。拟议项目的目的是分析具有这种环极分布的密生虫的遗传结构。对核基因和线粒体基因进行测序，我们首先想测试所报道的环极分布是否属实，或者只是由于存在神秘物种而人为造成的。第二，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，以及南大洋的物理和生物海洋学信息，调查种群之间的基因流的数量和方向。在第三步中，使用相同的DNA标记，我们希望测试南极大陆架上的浅水物种是否比具有广泛垂直分布范围的物种遭受了更多的冰川事件，因为这些物种可能已经逃到了深海。鉴于正在进行的和即将到来的环境变化，在南大洋作为一个快速变化的气候的结果，我们今天的内部和种间遗传多样性的南极Pycnogonida的分析是重要的基线研究监测南极生物群的反应不断变化的条件。

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.