Grant: Discovery Grants Program - Individual

As a consequence of human activity and global warming, the range and variability of environmental pressures that animals must cope with is constantly increasing. Understanding animal response to such varying environments is a first step towards uncovering the underlying forces driving complex biological processes, such as adaptation and microevolution of organisms. A broadly generalized approach, developed by J. Elser and colleagues attempts to link cellular allocation to organism function and to ecological dynamics. Briefly, rapidly growing organisms are thought to have low biomass C:P and N:P ratios that reflect an increased allocation to P-rich ribosomal RNA (rRNA) needed for rapid protein synthesis to support fast growth. Genetic mechanisms underlying high growth rate phenotypes implicate the structure and organisation of ribosomal RNA genes, notably heterogeneity in intergenic spacer (IGS) length. This implies that evolutionary processes can generate variation in a major life history trait (specific growth rate) and have consequences for ecological dynamics due to their effects on organismal elemental composition. The general objectives of my research program are: 1) to understand how changing environmental conditions impact physiological responses, mainly the growth rates of aquatic organisms; 2) to understand the adaptive responses of aquatic organisms by identifying and investigating functionally relevant genetic variation implicated in growth. As a model system I will focus mainly on Lake Saint-Pierre (LSP), the largest of the three fluvial lakes in the St. Lawrence River system, presenting important spatial and temporal environmental variations due to a highly complex hydrology. I will proceed to address the connections between growth rate, organism C:N:P and IGS length variation in yellow perch (Perca flavescens) under different conditions of nutrient supply. Using an integrated stoichiometric approach from molecular biology to ecology, my research program will address fundamentally important questions in evolutionary biology in general that have not been otherwise possible using conventional approaches.