Vitamin D status is heritable and under environment-dependent selection in the wild

<p>Vitamin D has a well-established role in skeletal health and is increasingly linked to chronic disease and mortality in humans and companion animals. Despite the clear significance of vitamin D for health and obvious implications for fitness under natural conditions, no longitudinal study has tested whether the circulating concentration of vitamin D is under natural selection in the wild. Here, we show that concentrations of dietary-derived vitamin D and endogenously-produced vitamin D metabolites are heritable and largely polygenic in a wild population of Soay sheep (<em>Ovis aries</em>). Vitamin D status was positively associated with female adult survival, and vitamin D status predicted female fecundity in particular, good environment years when sheep density and competition for resources was low. Our study provides evidence that vitamin D status has the potential to respond to selection, as well as new insights into how vitamin D metabolism is associated with fitness in the wild. </p>