FishLEGs · Life-history genes in fishes: bridging functional and evolutionary genetics for understanding life-history trait evolution

Life history is one of the most central concepts in biology. Numerous biological questions ultimately revolve around the causes and consequences of variation in reproduction and survival i.e. fitness. Tremendous effort has been put in establishing the causes and mechanisms for life history trait variation and trade-offs. But even in well studied model organisms, evolutionary genetic and functional genomic approaches are rarely combined, and thus the path from genotype to phenotype often remains a black box. A strategy to overcome this major hurdle has recently emerged, with the discovery of loci that explain exceptionally large proportions of the variation in various life history traits. These “life-history genes” offer new opportunities to study not just the why (evolution) but also the how (functional genetics) of life history trait variation. I will address critical outstanding questions by bridging functional and evolutionary genetics approaches to study multiple loci linked with life-history traits including age at maturity, migration timing and migration strategy in 3 fish species: Atlantic salmon, Rainbow trout/steelhead and Atlantic cod. The relatively simple genetic architecture of the traits, combined with the features of these species as model systems, offer a unique opportunity to finally reveal the genetic architectures, molecular mechanisms and ecological drivers that translate large-effect genotypes into adapted life history phenotypes, and examine how evolution shapes these processes. In FishLEGs I will: i) characterize the molecular functions behind genotype-life history associations; ii) elucidate life history trait reaction norms and evolution in variable environments and iii) determine the strength of natural and sexual selection on life history traits, their sex specific effects, and model the evolutionary consequences. Life history research also has societal relevance for health, sustainable fisheries, conservation and climate resilience.