title: Variation at the DRD4 locus is associated with wariness and local site selection in urban black swans.
abstract: BACKGROUND
  Interactions between wildlife and humans are increasing. Urban animals are often less wary of humans than their non-urban counterparts, which could be explained by habituation, adaptation or local site selection. Under local site selection, individuals that are less tolerant of humans are less likely to settle in urban areas. However, there is little evidence for such temperament-based site selection, and even less is known about its underlying genetic basis. We tested whether site selection in urban and non-urban habitats by black swans (Cygnus atratus) was associated with polymorphisms in two genes linked to fear in animals, the dopamine receptor D4 (DRD4) and serotonin transporter (SERT) genes.
  
  
  RESULTS
  Wariness in swans was highly repeatable between disturbance events (repeatability = 0.61) and non-urban swans initiated escape from humans earlier than urban swans. We found no inter-individual variation in the SERT gene, but identified five DRD4 genotypes and an association between DRD4 genotype and wariness. Individuals possessing the most common DRD4 genotype were less wary than individuals possessing rarer genotypes. As predicted by the local site selection hypothesis, genotypes associated with wary behaviour were over three times more frequent at the non-urban site. This resulted in moderate population differentiation at DRD4 (FST = 0.080), despite the sites being separated by only 30 km, a short distance for this highly-mobile species. Low population differentiation at neutrally-selected microsatellite loci and the likely occasional migration of swans between the populations reduces the likelihood of local site adaptations.
  
  
  CONCLUSIONS
  Our results suggest that wariness in swans is partly genetically-determined and that wary swans settle in less-disturbed areas. More generally, our findings suggest that site-specific management strategies may be necessary that consider the temperament of local animals.
authors.affiliation: Applied Ecology Research Group and Institute for Sustainability and Innovation, College of Engineering and Science, Victoria University-Footscray Park Campus, PO Box 14428, Melbourne MC, VIC, 8001, Australia. wouter.v.dongen@gmail.com.|Centre for Integrative Ecology, School of Life and Environmental Sciences, Faculty of Science, Engineering and the Built Environment, Deakin University, 221 Burwood Highway, Burwood, VIC, 3125, Australia. wouter.v.dongen@gmail.com.
authors.forename: Wouter F D
authors.initials: WF
authors.lastname: van Dongen
authors.affiliation: Applied Ecology Research Group and Institute for Sustainability and Innovation, College of Engineering and Science, Victoria University-Footscray Park Campus, PO Box 14428, Melbourne MC, VIC, 8001, Australia. Randall.Robinson@vu.edu.au.
authors.forename: Randall W
authors.initials: RW
authors.lastname: Robinson
authors.affiliation: Centre for Integrative Ecology, School of Life and Environmental Sciences, Faculty of Science, Engineering and the Built Environment, Deakin University, 221 Burwood Highway, Burwood, VIC, 3125, Australia. mike.weston@deakin.edu.au.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Weston
authors.affiliation: Department of Zoology, University of Melbourne, Melbourne, VIC, 3010, Australia. r.mulder@unimelb.edu.au.
authors.forename: Raoul A
authors.initials: RA
authors.lastname: Mulder
authors.affiliation: Applied Ecology Research Group and Institute for Sustainability and Innovation, College of Engineering and Science, Victoria University-Footscray Park Campus, PO Box 14428, Melbourne MC, VIC, 8001, Australia. Patrick.Guay@vu.edu.au.
authors.forename: Patrick-Jean
authors.initials: PJ
authors.lastname: Guay
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D046090:Anseriformes / Q000235:genetics / Q000502:physiology*; D030161:Avian Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D004924:Escape Reaction; D006802:Human Activities; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D050638:Receptors, Dopamine D4 / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D030161:Avian Proteins; D050638:Receptors, Dopamine D4