A genome informatics approach to discover the genetic determinants of the evolution of parasitism in nematode worms.

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Species of nematodes are ubiquitous, and significant parasites of animals and plants. This parasitism has evolved multiple times independently from free-living ancestral species. The biological mechanisms that support parasitism are encoded in the nematodes’ genomes. The long-term objectives of my research program are to understand which regions of the genome evolved, and how this leads to the origin and maintenance of the behaviour and biochemical traits that we observe in today’s parasitic nematodes. Using a combination of genomics, bioinformatics and evolutionary biology approaches, my research program examines the evolution of gene duplications and growth of gene families in the genomes of both free-living and parasitic nematodes of livestock animals. Large gene families are implicated in responding to an organism’s response to its environment. Changes in these gene families frequently correlate to the adaptation of a new environment, which can lead to the emergence of a new species. The fully sequenced genomes of over 20 nematode species of interest – Caenorhabditis (free-living) and Strongylida (livestock parasites) – enable us to test various key questions in species evolution. We will determine whether different gene families are evolving rapidly in free-living and parasitic species. We will identify those gene families that are evolving in parallel in species that have independently adapted to the parasitism of cattle. The genetic determinants that enable closely related species of Haemonchus to adapt to parasitism of different hosts will also be identified. Finally, we will use gene expression and protein structural data to predict how protein function changes in these important gene families. Overall, these research objectives aim to significantly improve our understanding of how the genome evolves in response to new environments and how these changes support the adaptation and fixation in that new environment. This has implications across a broad range of species, not only parasites.