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

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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.