MC1R genotype and plumage colouration in the zebra finch (Taeniopygia guttata): population structure generates artefactual associations.
Polymorphisms at the melanocortin-1 receptor (MC1R) gene have been linked to coloration in many vertebrate species. However, the potentially confounding influence of population structure has rarely been controlled for. We explored the role of the MC1R in a model avian system by sequencing the coding region in 162 zebra finches comprising 79 wild type and 83 white individuals from five stocks. Allelic counts differed significantly between the two plumage morphs at multiple segregating sites, but these were mostly synonymous. To provide a control, the birds were genotyped at eight microsatellites and subjected to Bayesian cluster analysis, revealing two distinct groups. We therefore crossed wild type with white individuals and backcrossed the F1s with white birds. No significant associations were detected in the resulting offspring, suggesting that our original findings were a byproduct of genome-wide divergence. Our results are consistent with a previous study that found no association between MC1R polymorphism and plumage coloration in leaf warblers. They also contribute towards a growing body of evidence suggesting that care should be taken to quantify, and where necessary control for, population structure in association studies.
Department of Animal Behaviour, University of Bielefeld, Bielefeld, Germany.
Joseph I
JI
Hoffman
Department of Animal Behaviour, University of Bielefeld, Bielefeld, Germany ; Behavioural Ecology Group, Department of Animal Sciences, Wageningen University, Wageningen, The Netherlands.
E Tobias
ET
Krause
Department of Animal Behaviour, University of Bielefeld, Bielefeld, Germany.
Katrin
K
Lehmann
Department of Animal Behaviour, University of Bielefeld, Bielefeld, Germany.
Oliver
O
Krüger
D000483:Alleles; D000818:Animals; D016477:Artifacts; D001499:Bayes Theorem; D003116:Color; D005241:Feathers; D005260:Female; D015870:Gene Expression; D005838:Genotype; D008297:Male; D018895:Microsatellite Repeats; D009426:Netherlands; D016366:Open Reading Frames; D010858:Pigmentation / Q000235:genetics*; D011110:Polymorphism, Genetic; D011157:Population Dynamics; D044102:Receptor, Melanocortin, Type 1 / Q000235:genetics*; D017422:Sequence Analysis, DNA; D020308:Songbirds / Q000235:genetics*
D044102:Receptor, Melanocortin, Type 1