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

• The extent of pleiotropy and epistasis in quantitative traits remains equivocal. In the caseof pleiotropy, multiple quantitative trait loci are often taken to be pleiotropic if theirconfidence intervals overlap, without formal statistical tests being used to ascertain ifthese overlapping loci are statistically significantly pleiotropic. Additionally, the degreeto which the genetic correlations between phenotypic traits are reflected in thesepleiotropic quantitative trait loci is often variable, especially in the case of antagonisticpleiotropy. Similarly, the extent of epistasis in various morphological, behavioural andlife-history traits is also debated, with a general problem being the sample sizes requiredto detect such effects. Domestication involves a large number of trade-offs, which arereflected in numerous behavioural, morphological and life-history traits which haveevolved as a consequence of adaptation to selective pressures exerted by humans andcaptivity. The comparison between wild and domestic animals allows the geneticanalysis of the traits that differ between these population types, as well as being ageneral model of evolution. Using a large F2 intercross between wild and domesticatedchickens, in combination with a dense SNP and microsatellite marker map, bothpleiotropy and epistasis were analysed. The majority of traits were found to segregate in11 tight ‘blocks’ and reflected the trade-offs associated with domestication. These blockswere shown to have a pleiotropic ‘core’ surrounded by more loosely linked loci. Incontrast, epistatic interactions were almost entirely absent, with only six pairs identifiedover all traits analysed. These results give insights both into the extent of such blocks inevolution and the development of domestication itself.

Ämnesord

LANTBRUKSVETENSKAPER  -- Husdjursvetenskap (hsv//swe)

AGRICULTURAL SCIENCES  -- Animal and Dairy Sience (hsv//eng)

LANTBRUKSVETENSKAPER  -- Veterinärmedicin (hsv//swe)

AGRICULTURAL SCIENCES  -- Veterinary Science (hsv//eng)

Nyckelord

domastication

epistasis

pleiotropy

QTL

NATURAL SCIENCES

NATURVETENSKAP

VETERINARY MEDICINE

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