QTL detection and allelic effects for growth and fat traits in outbred pig populations

Genetics Selection Evolution

Chris S Haley¹  Peter M Visscher²  Yoshitaka Nagamine¹ 

[1] Roslin Institute (Edinburgh), Midlothian, EH25 9PS, UK;Institute of Cell, Animal and Population Biology, University of Edinburgh, West Mains Road, Edinburgh, EH9 3JT, UK

关键词: pig;    heritability;    variance component;    IBD;    QTL mapping;   

Others  :  1094359
DOI  :  10.1186/1297-9686-36-1-83

 received in 2003-02-17, accepted in 2003-09-25,  发布年份 2004

【 摘 要 】

Quantitative trait loci (QTL) for growth and fatness traits have previously been identified on chromosomes 4 and 7 in several experimental pig populations. The segregation of these QTL in commercial pigs was studied in a sample of 2713 animals from five different populations. Variance component analysis (VCA) using a marker-based identity by descent (IBD) matrix was applied. The IBD coefficient was estimated with simple deterministic (SMD) and Markov chain Monte Carlo (MCMC) methods. Data for two growth traits, average daily gain on test and whole life daily gain, and back fat thickness were analysed. With both methods, seven out of 26 combinations of population, chromosome and trait, were significant. Additionally, QTL genotypic and allelic effects were estimated when the QTL effect was significant. The range of QTL genotypic effects in a population varied from 4.8% to 10.9% of the phenotypic mean for growth traits and 7.9% to 19.5% for back fat trait. Heritabilities of the QTL genotypic values ranged from 8.6% to 18.2% for growth traits, and 14.5% to 19.2% for back fat. Very similar results were obtained with both SMD and MCMC. However, the MCMC method required a large number of iterations, and hence computation time, especially when the QTL test position was close to the marker.

【 授权许可】

   
2004 INRA, EDP Sciences