Comparative genomics of leeches: anticoagulants, bacterial symbionts and evolutionary relationships

我的研究计划的总体目标是了解行为，生态学和形态学的进化转变，以及阐明生物和遗传多样性的起源和分布，这些主题对生物和生物的自然历史至关重要。为了实现这一目标，需要了解任何这些特征变化背后的基因组基础。这个基础将证明事件的方向和时间，并增加我们对负责潜在变化的基因组单位的理解。水蛭（水蛭、小龙虾蠕虫和棘足动物）提供了一个很好的系统，在这个系统中，由于在生态、行为和形态上的相似性，可以测试基因组组成的共性假设。这是由于摄食行为的多样性、栖息地的选择、形态的可塑性以及该目所表现出的世界性分布。很少有其他类群可以拥有如此广泛的栖息地和行为范围，同时在物种数量方面也接近（水蛭的n=~700）。尽管如此，我们对具有不同分布、生态和行为的水蛭物种之间的共同和不同特征知之甚少。拟议的研究将通过四个主要目标来研究水蛭的进化：（目标1）产生新的基因组水平测序数据，以证明支持多种特征集的基因组骨干（目标2）通过利用约100个末端的目标捕获序列推断水蛭的全序列系统发育假说；（目的3）在广泛的水蛭多样性范围内确定唾液腺分泌抗凝剂的所有主要家族，以便(i)允许更好地了解水蛭分泌的蛋白质，（ii）能够比较吸血和非吸血物种之间的抗凝剂多样性，（iii）揭示蛋白质家族扩展的驱动因素，（iv）发现新的抗凝剂；（目的4）对舌蛭类水蛭的大量细菌基因组进行测序，以确定(i)它们的主要功能是否为提供水蛭严格的血液饮食所缺乏的B族维生素；（ii）证明细菌的进化史。我们将寻找其他功能，并研究B族维生素的产生是否在不同的细菌共生体家族中是共同的。重要的是，我的研究项目是针对HQP的培训，并且是模块化的，以允许项目的独立性。学生将在四大洲（澳大利亚、北美、南美和亚洲）进行实地考察，并接受尖端测序技术和下游生物信息学方面的培训。通过这项研究，HQP将在多个实验室和实地工作技能方面获得全面的生物技术培训，这将使他们在申请未来职位时处于领先地位。

The overall goal of my research program is to understand evolutionary transitions in behaviour, ecology and morphology, as well as to shed light on the origin and distribution of biological and genetic diversity, topics that are fundamental to the biology and natural history of organisms. To achieve this goal, an understanding of the genomic basis that underlies changes to any of these characteristics is required. This foundation will evince the direction and timing of events and increase our understanding of the genomic units that are responsible for the potential change. Hirudinea (leeches, crayfish worms and acanthobdellids) presents an excellent system in which to test hypotheses of commonalities in genomic makeup due to similarities in ecology, behaviour and morphology. This is due to the diverse set of feeding behaviours, habitat choices, morphological plasticity, and the cosmopolitan distribution that the order exhibits. Few other taxa can boast such wide habitat and behavioural ranges while also being approachable in terms of species numbers (n=~700 for leeches). Despite this, we know very little about the common and divergent features between leech species with separate distributions, ecology and behaviour. The proposed research will investigate the evolution of leeches through four broad objectives: (OBJECTIVE 1) generate new genome-level sequencing data to evince the genomic backbone that supports the diverse set of features (OBJECTIVE 2) infer an order-wide phylogenomic hypothesis for leeches by leveraging target-capture sequences for ~100 terminals; (OBJECTIVE 3) identify all major families of salivary gland-secreted anticoagulants across a broad range of leech diversity, in order to (i) allow for a better understanding of the proteins secreted by leeches, (ii) enable comparisons of anticoagulant diversity between bloodfeeding and non-bloodfeeding species, (iii) expose the drivers of protein family expansions and (iv) uncover new anticoagulants; (OBJECTIVE 4) to sequence numerous bacterial genomes of associates of glossiphoniid leeches to assert (i) whether or not their main function is to provide B vitamins that are otherwise lacking from the leeches' strict diet of blood and (ii) to evince the evolutionary histories of the bacteria. We will search for additional functions and investigate if the production of B vitamins is common throughout the different families of bacterial symbionts. Importantly, my research program is geared towards the training of HQP and is modular to allow for independence in projects. Students will be trained in fieldwork conducted on four continents (Australia, North America, South America and Asia), and in cutting-edge sequencing technologies coupled with downstream bioinformatics. Through this research, HQP will receive a well-rounded state of the art biological training in multiple lab-based and fieldwork skills that will place them at the front of the curve when applying for future positions.