Phylogenomic analysis of Nereididae (Annelida)

沙蚕科（Nereididae）是一组环节动物蠕虫，可以在世界各地的海洋，半咸水或淡水栖息地发现，已描述了650多个物种。沙蚕类环节动物在进化发育生物学、生殖生物学和生态学等方面有着广泛的研究。沙蚕Platynereis dumerilii是目前研究最好的散轮藻模式生物。许多重要的实验室技术已经建立了这个物种和基因表达参与胚胎发生，节的形成和再生，神经系统和眼睛的发育进行了详细的研究。尽管沙蚕科是研究得最好的环节动物类群之一，但迄今为止，这一类群的生殖发育尚未得到很好的解决。然而，知道的系统发育关系的Platynereis dumerilii其最近的亲属是必要的研究的步骤，生活史，基因组和形态进化的这一重要model.The主要目标是重建一个良好的支持nereidids的系统发育。通过使用混合目标富集和随后的Illumina测序，将进行基于约65个物种和96个个体（涵盖选定物种的不同地理来源）的约250个基因座的基因组分析，代表沙蚕的多样性。目标富集的诱饵将基于本项目中产生的10个选定沙蚕物种的一组转录组。这一系统发育将被用来检验目前沙蚕科的分类是否与单系群相一致。此外，这一系统发育框架将最终提供一个稳定的放置模式环节动物Platynereis dumerilii内沙蚕。在此基础上，通过祖先状态重建，推测蠕虫的生殖方式、生活方式和栖息地偏好的演化。

Nereididae are a group of annelid worms that can be found worldwide in marine, brackish, or freshwater habitats and more than 650 species have been described. Nereidid annelids have been extensively studied in evolutionary developmental biology, reproductive biology and ecology. The nereidid Platynereis dumerilii became the best investigated model organism of Lophotrochozoa in general. Many important laboratory techniques have been established for this species and gene expression involved in embryogenesis, segment formation and regeneration, development of the nervous system and eyes are studied in detail. Even though nereidids are one of the best investigated annelid taxa, the phylogeny of this group has not been well-resolved so far. However, knowing the phylogenetic relationships of Platynereis dumerilii to its closest relatives is necessary for studying the steps that underlie life history, genomic, and morphological evolution of this important model.The main objective of this project is to reconstruct a well-supported phylogeny for nereidids. By using hybrid target enrichment with subsequent Illumina sequencing, a phylogenomic analysis based on approximately 250 loci derived for around 65 species and 96 individuals (covering different geographic origins for selected species) representing the diversity of nereidids will be conducted. Baits for target enrichment will be based on a set of transcriptomes from 10 selected nereidid species generated within this project. This phylogeny will be used to test if the current classification of nereidids coincides with monophyletic groups. Moreover, this phylogenetic framework will finally provide a stable placement of the model annelid Platynereis dumerilii within nereidids. Based on this phylogeny, ancestral state reconstruction will be used to infer the evolution of reproductive modes, life-style and habitat preference of nereidid worms.