The causes and consequences of individual recombination rate variation.

Variation in recombination rate (RR) is likely to have direct consequences levels of genetic diversity, effectiveness of selection and ultimately, fitness within individuals. We are currently using dense genomic, phenotypic and environmental data from wild populations of Soay sheep (Ovis aries), red deer (Cervus elaphus) and house sparrows (Passer domesticus) to estimate individual RR, to investigate its heritability, how it varies within and between individuals, and the relationship between RR and individual fitness.

Main collaborators: Josephine Pemberton (Edinburgh), Jon Slate (Sheffield), Henrik Jensen (NTNU, Trondheim), Bernt-Erik Saether (NTNU, Trondheim).

Sex differences in recombination rates.

Sex is consistently one of the strongest correlates with recombination rate across taxa, with most species being either achiasmic (i.e. recombination is absent in one sex) or heterochiasmic (i.e. RR differs between the sexes). Achiasmy is well explained by the Haldane-Huxley rule, but there remains little consensus on drivers of heterochiasmy, as its degree and direction can vary even between closely related species. As theories continue to proliferate, suitable genomic data to test them has been limited to a very small
number of model species. At present we are curating new, publically available recombination mapping data for potential meta-analyses of ecological and genomic drivers of heterochiasmy.

Main collaborator: Thomas Lenormand (CEFE, Montpellier).

Understanding the genetic basis of life-history variation in wild Atlantic salmon (Salmo salar).

Classical life history theory predicts that trade-offs between reproductive success and survival should lead to the evolution of an optimal strategy in a population. However, Atlantic salmon show large variation in mating strategies within and between populations, and in general, there remains a poor understanding of genetic and physiological mechanisms underlying this variation. Salmon in the Teno river in Northern Finland show a particularly large variety of life-history strategies, and have been subject to long-term scale sampling by local fishermen. We are currently applying genome-wide SNP approaches to archived DNA samples to help identify regions of the genome associated with life-history strategies and to understand their maintenance and evolution.

Main collaborators: Craig Primmer (Turku), Eero Niemelä & Jaakko Erkinaro (RKTL), Sigbjørn Lien & Matthew Kent (CIGENE)

Population genomic analyses in nine-spined sticklebacks.

Nine-spined stickleback (Pungitius pungitius) populations in Fennoscandia display a large degree of morphological, behavioural and life-history variation after post-glacial recolonisation. We used a restriction-site-associated (RAD) sequencing approach to characterise genome-wide patterns of differentiation and variability in populations across a range of habitats.

Main collaborators: Matthieu Bruneaux, Anti Vasemägi & Craig Primmer (Turku), Juha Merilä (Helsinki)

Understanding the maintenance of genetic variation in sexually selected traits.

The maintenance of genetic variation in sexually select traits has become a long-discussed paradox in the field of evolutionary biology. In wild Soay sheep, large horned males have higher reproductive success, but males with small or deformed horns persist within the population. We pinpointed the causal genetic mechanisms influencing horn development using genome-wide association studies and tested the most commonly proposed explanations for the maintenance of sexually-selected genetic variation, such as genic capture (“good genes”), sexually antagonistic selection, and trade-offs between sexual and non-sexual fitness (i.e. reproductive success vs. survival).

Main collaborators: Jon Slate (Sheffield) and Josephine Pemberton (Edinburgh)