Grant: Discovery Grants Program - Individual

The long-term objective of my research program is to determine how polyploidy affects physiological processes in vertebrates, using fish as experimental models. Polyploids have more than the normal two (diploid) chromosome sets in their genomes: triploids have three, tetraploids have four, etc. Polyploidy has played an important role in vertebrate evolution by providing redundant genes that can mutate without causing lethality, thus allowing them to acquire novel function. A consequence of polyploidy is increased cell volume in cells for which the nucleus occupies a relatively large proportion of the total cell volume, resulting in reduced cell numbers, reduced cellular and nuclear surface area per unit volume, and increased intracellular diffusion distances. These changes likely impose physiological constraints on individual animals that counterbalance the long-term (evolutionary) genetic benefits of polyploidy. My research aims to determine the nature of such constraints, thereby helping to assess the broader significance of polyploidy as a driver of evolution. My focus in this proposal is on how polyploidy affects environmental tolerances, osmoregulatory ability, metabolism, and erythrocyte dynamics. This research will be conducted using both salmonids - relatively large, easily cultured fish of importance for aquaculture and fisheries management - and zebrafish - a popular aquarium fish that has become one of the most important model species for research on vertebrate development. I will train five undergraduate and three graduate students with funding from this grant. In addition to the basic knowledge gained from this research, it will benefit aquaculture and fisheries management in Canada, as triploidy is seen as a valuable tool for creating reproductively-sterile populations of fish. Understanding the limitations of triploids will lead to improvements in their husbandry and will ensure that their welfare is properly considered.