Publications by authors named "Ronan James O'Sullivan"

We investigated ancestry, kinship, and health in individuals from three cemeteries in Finland: Tampere Vilusenharju and Pälkäne Ristiänmäki (11th-12th centuries) and Rauniokirkko (13th-19th century). The oldest burials provide insights into Finland's medieval population, otherwise poorly known due to poor bone preservation. Using ancient genomic data, contemporary Finnish Biobank data, and identity-by-descent (IBD) analyses, we identified strong regional continuity between the medieval and modern Finnish populations and evidence for mobility within Finland and between Finland and Scandinavia.

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Age at maturity is an important life-history trait, often showing sex-specific variation, contributing to life-history diversity in many species. Atlantic salmon ( Salmo salar ) are an excellent model system to investigate genetic and environmental factors affecting sex-specific maturation, yet few laboratory studies have focused on females as they mature later than males, on average. Using a 4-year common-garden experiment of Atlantic salmon, we assessed the influence of diet (low-fat vs.

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The deliberate release of captive-bred individuals, the accidental escape of domesticated strains, or the invasion of closely related conspecifics into wild populations can all lead to introgressive hybridization, which poses a challenge for conservation and wildlife management. Rates of introgression and the magnitude of associated demographic impacts vary widely across ecological contexts. However, the reasons for this variation remain poorly understood.

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Males and females are often subject to different and even opposing selection pressures. When a given trait has a shared genetic basis between the sexes, sexual conflict (antagonism) can arise. This can result in significant individual-level fitness consequences that might also affect population performance, whilst anthropogenic environmental change can further exacerbate maladaptation in one or both sexes driven by sexual antagonism.

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The release of captive-bred animals into the wild is commonly practised to restore or supplement wild populations but comes with a suite of ecological and genetic consequences. Vast numbers of hatchery-reared fish are released annually, ostensibly to restore/enhance wild populations or provide greater angling returns. While previous studies have shown that captive-bred fish perform poorly in the wild relative to wild-bred conspecifics, few have measured individual lifetime reproductive success (LRS) and how this affects population productivity.

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Comparing observed versus theoretically expected evolutionary responses is important for our understanding of the evolutionary process, and for assessing how species may cope with anthropogenic change. Here, we document directional selection for larger female size in Atlantic salmon, using pedigree-derived estimates of lifetime reproductive success as a fitness measure. We show the trait is heritable and, thus, capable of responding to selection.

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