Evolutionary, developmental, and physiological genetics of salmonid fishes

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Understanding how genes interact with one another and with their surrounding environment to bring about changes in individuals remains one of the greatest challenges in modern biology. We are now gaining an understanding of many genes that are important in bringing about developmental change and adaptation to novel environmental situations, yet we still lack precise knowledge on which genes, from many interacting genetic elements, may be the most important determinants of these processes. We are also a long way from understanding how all the genes in the vertebrate body are organized with respect to one another, and whether the retention of multiple copies of genes are important in adaptation and survival. Most vertebrate species have descended from ancestors that have undergone at least two whole genome duplications (i.e. doubling of all the genes and chromosomes in their body), while modern bony fishes have descended from an ancestor that experienced one additional whole genome duplication. It has been suggested that this extra round of genome duplication accounts for why we have many more fish species (~30,000) compared to all other vertebrate classes combined. Additionally, some fishes (e.g. salmonids such as salmon and trout), have undergone one extra genome duplication (i.e. have undergone 4 rounds of genome duplication). Genes influencing growth and timing of important life-history traits (e.g. age of sexual maturity and time of seasonal reproduction), are some of the most important genes influencing fish survival in the natural world. This research seeks to identify the most important genetic elements influencing growth and life-history adaptation traits in salmonid fishes. This research also seeks to understand how genes are arranged, and retained or lost within the genomes of salmonid fishes. These species are living testaments to complex genome changes that have occurred in vertebrates, and thus knowledge from this research will further our understanding of vertebrate genome evolution. Additionally, the study of genetic interactions may help us to understand how new populations form, and whether genetic interactions help promote or inhibit genetic exchange among populations.