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Research article - Peer-reviewed, 2010

The genetic architecture of domestication in the chicken: effects of pleiotropy and linkage

Wright, D.; Rubin, C. -J.; Barrio, A. Martinez; Schutz, K.; Kerje, S.; Brandstrom, H.; Kindmark, A.; Jensen, P.; Andersson, L.


The extent of pleiotropy and epistasis in quantitative traits remains equivocal. In the case of pleiotropy, multiple quantitative trait loci are often taken to be pleiotropic if their confidence intervals overlap, without formal statistical tests being used to ascertain if these overlapping loci are statistically significantly pleiotropic. Additionally, the degree to which the genetic correlations between phenotypic traits are reflected in these pleiotropic quantitative trait loci is often variable, especially in the case of antagonistic pleiotropy. Similarly, the extent of epistasis in various morphological, behavioural and life-history traits is also debated, with a general problem being the sample sizes required to detect such effects. Domestication involves a large number of trade-offs, which are reflected in numerous behavioural, morphological and life-history traits which have evolved as a consequence of adaptation to selective pressures exerted by humans and captivity. The comparison between wild and domestic animals allows the genetic analysis of the traits that differ between these population types, as well as being a general model of evolution. Using a large F(2) intercross between wild and domesticated chickens, in combination with a dense SNP and microsatellite marker map, both pleiotropy and epistasis were analysed. The majority of traits were found to segregate in 11 tight 'blocks' and reflected the trade-offs associated with domestication. These blocks were shown to have a pleiotropic 'core' surrounded by more loosely linked loci. In contrast, epistatic interactions were almost entirely absent, with only six pairs identified over all traits analysed. These results give insights both into the extent of such blocks in evolution and the development of domestication itself.


domestication; epistasis; pleiotropy; QTL

Published in

Molecular Ecology
2010, volume: 19, number: 23, pages: 5140-5156

Authors' information

Wright, Dominic
Linköping University
Rubin, Carl-Johan
Uppsala University
Martínez Barrio, Álvaro
Schütz, Karin (Schütz, Karin)
Swedish University of Agricultural Sciences, Department of Animal Environment and Health
Kerje, Susanne
Brändström, Helena
Kindmark, Andreas
Jensen, Per
Andersson, Leif
Uppsala University

UKÄ Subject classification

Animal and Dairy Science
Veterinary Science

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