Intraspecific biodiversity of fishes and their monogenean parasites: pattern and process

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My research investigates biological diversity within species in aquatic environments. I am trying to answer three general questions: (1) How connected are populations? (2) How much adaptive genetic diversity exists within species, and what are some of the key processes generating it? (3) When, and by what ecological processes does genetic diversity within species reach the point in which populations are actually distinct species? My approach to answering these questions includes paired population genetic analyses of fishes and their monogenean parasites. The parasites are included for the following reasons: First, their host specificity suggests that their population structure should mirror that of their fish hosts, but their smaller effective population sizes and very short generation times lead to the prediction that they will actually show much more genetic structure than their hosts; thus, they have the potential to act as "biological magnifying glasses" revealing cryptic details of their host fish population structure. Second, these parasites, which belong to the genus Gyrodactylus, are believed to have diversity rivalling that of fishes, and they are ecologically and at times economically important (because of their impacts on some wild and aquacultured fish populations), yet almost nothing is known about their intraspecific diversity; thus, they deserve study in their own right. I am using 'genome scans' based on advanced DNA sequencing techniques to identify genomic regions in both the fishes and their parasites that show adaptive genetic variation, and that, in some cases, are associated with the development of new species. Several fish species, including sticklebacks, Atlantic Cod, guppies, Rainbow Smelt (and their parasites), will serve as experimental models for this research, but the results should provide general insights into the patterns and extent of intraspecific biodiversity in aquatic environments, and the ecological and evolutionary processes that underlie it. They will also help inform conservation and management efforts. This research program will lead to the training of a number of young scientists in advanced methods of genomic analysis and in aquatic biodiversity, both areas of importance to Canada.