title: Vitamin D status predicts reproductive fitness in a wild sheep population.
abstract: Vitamin D deficiency has been associated with the development of many human diseases, and with poor reproductive performance in laboratory rodents. We currently have no idea how natural selection directly acts on variation in vitamin D metabolism due to a total lack of studies in wild animals. Here, we measured serum 25 hydroxyvitamin D (25(OH)D) concentrations in female Soay sheep that were part of a long-term field study on St Kilda. We found that total 25(OH)D was strongly influenced by age, and that light coloured sheep had higher 25(OH)D3 (but not 25(OH)D2) concentrations than dark sheep. The coat colour polymorphism in Soay sheep is controlled by a single locus, suggesting vitamin D status is heritable in this population. We also observed a very strong relationship between total 25(OH)D concentrations in summer and a ewe's fecundity the following spring. This resulted in a positive association between total 25(OH)D and the number of lambs produced that survived their first year of life, an important component of female reproductive fitness. Our study provides the first insight into naturally-occurring variation in vitamin D metabolites, and offers the first evidence that vitamin D status is both heritable and under natural selection in the wild.
authors.affiliation: Royal (Dick) School of Veterinary Studies and The Roslin Institute, Division of Veterinary Clinical Studies, The University of Edinburgh, Hospital for Small Animals, Easter Bush Veterinary Centre, Roslin, Midlothian, EH25 9RG UK.
authors.forename: Ian
authors.initials: I
authors.lastname: Handel
authors.affiliation: Institutes of Evolutionary Biology School of Biological Sciences, University of Edinburgh, Edinburgh, UK.|Infection and Immunity Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Watt
authors.affiliation: Institutes of Evolutionary Biology School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
authors.forename: Jill G
authors.initials: JG
authors.lastname: Pilkington
authors.affiliation: Institutes of Evolutionary Biology School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
authors.forename: Josephine M
authors.initials: JM
authors.lastname: Pemberton
authors.affiliation: Royal (Dick) School of Veterinary Studies and The Roslin Institute, Division of Veterinary Clinical Studies, The University of Edinburgh, Hospital for Small Animals, Easter Bush Veterinary Centre, Roslin, Midlothian, EH25 9RG UK.
authors.forename: Alastair
authors.initials: A
authors.lastname: Macrae
authors.affiliation: Royal (Dick) School of Veterinary Studies and The Roslin Institute, Division of Veterinary Clinical Studies, The University of Edinburgh, Hospital for Small Animals, Easter Bush Veterinary Centre, Roslin, Midlothian, EH25 9RG UK.
authors.forename: Philip
authors.initials: P
authors.lastname: Scott
authors.affiliation: Moredun Research Institute, Midlothian, UK.
authors.forename: Tom N
authors.initials: TN
authors.lastname: McNeilly
authors.affiliation: Specialist Assay Laboratory, 2nd Floor, CSB3, Manchester, UK.
authors.forename: Jacqueline L
authors.initials: JL
authors.lastname: Berry
authors.affiliation: Royal (Dick) School of Veterinary Studies and The Roslin Institute, Division of Veterinary Clinical Studies, The University of Edinburgh, Hospital for Small Animals, Easter Bush Veterinary Centre, Roslin, Midlothian, EH25 9RG UK.
authors.forename: Dylan N
authors.initials: DN
authors.lastname: Clements
authors.affiliation: Institutes of Evolutionary Biology School of Biological Sciences, University of Edinburgh, Edinburgh, UK.|Infection and Immunity Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Nussey
authors.affiliation: Royal (Dick) School of Veterinary Studies and The Roslin Institute, Division of Veterinary Clinical Studies, The University of Edinburgh, Hospital for Small Animals, Easter Bush Veterinary Centre, Roslin, Midlothian, EH25 9RG UK.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Mellanby
mesh_terms: D000367:Age Factors; D000818:Animals; D005260:Female; D006200:Hair Color; D010641:Phenotype; D010809:Physical Fitness; D012098:Reproduction; D012756:Sheep; D034561:Sheep, Domestic; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D