Systematics & phylogenomics
The evolution of sea slug colour
Ecological & evolutionary genomics
Our group integrates molecular and morphological data to refine molluscan taxonomy and improve the resolution of molluscan phylogeny. Currently, we're untangling the systematics of two western Atlantic genera, Chromolaichma and Felimida, and we're resolving deeper chromodorid phylogeny using sequence capture. Beyond heterobranchs, our group is also fascinated by parasitic eulimid gastropods for which very little molecular data exists for phylogenetic reconstruction. We're working towards building molecular datasets for these understudied molluscan groups, and more generally, our group is passionate about improving genomic resources for invertebrates.
Colour pattern variation, and the processes governing it, is of central interest to our group. Our previous work on Chromodoris demonstrated that colour is highly variable and largely unreliable as a diagnostic morphological character. Most notably, we uncovered a near-perfect case of mimicry in Western Australian Chromodoris. From these early findings, we've become interested in the mechanisms that drive phenotypic diversity in shell-less gastropods ('sea slugs'), and particularly, the role that introgression might play in driving the evolution of mimicry, and colour patterns more broadly, in sea slugs.
Our group has since expanded this work to include additional polymorphic dorid systems, including the European sea lemon (Doris pseudoargus). We've generated large SNP datasets and collected samples for RNAseq so we can combine genomic and gene expression data to identify regions controlling colour pattern polymorphism in sea slugs.
Biodiversity is structured at different scales, meaning that to gain a deeper understanding of it, we need to hone in on the microevolutionary processes driving this diversity. We also know that climate change is driving extinctions in many taxonomic groups, and in fact, molluscs are one of the most endangered groups of animal in North America. Our group scans and compares genomes from multiple populations and species to look for signatures of local adaptation and integrates this information with ecological modelling to forecast biodiversity response to climate change. We're currently applying these methods to the highly endangered freshwater pearl mussel (Margaritifera margaritifera), using non-invasive genetic sampling for downstream sequencing. This work is being led by Victoria Gillman, a PhD student in our group, and it stems from previous work completed during Kara's postdoc.
Through the course of my career I've worked with many museum collections in Canada, the UK and Australia, among others. In fact, museum collections are an incredibly important resource for biodiversity research and form the basis of many projects in our lab. We use ethanol-preserved specimens (some >15yrs in age) for our sequence capture work, and since 2014, we've been trialling DNA extraction methods on dry mollusc shells. These collections allow us to fill important taxonomic gaps in our work, especially for endangered species that are otherwise difficult to sample in the wild.
Our group participates in a number of local and global barcoding initiatives as part of BIOSCAN, and more recently, has begun to apply eDNA metabarcoding to better understand invertebrate biodiversity in critically important habitats. Currently, PhD student Ethan Ross is comparing the recovery of benthic invertebrate diversity from aqueous and sedimentary eDNA sampled from Scottish seagrass beds. As part of this work, we continue to build barcode reference libraries to support future eDNA applications.
We're fascinated by many different invertebrate systems and evolutionary questions. We're starting new projects on terrestrial snail biodiversity and evolution, with a focus on taxa in understudied tropical forests. We're particularly interested in the phenomenon of malacophily and understanding more about pollination services in molluscs.