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A two‐step approach to map quantitative trait loci for meat quality in connected porcine F 2 crosses considering main and epistatic effects
Author(s) -
Stratz P.,
Baes C.,
Rückert C.,
Preuss S.,
Bennewitz J.
Publication year - 2013
Publication title -
animal genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.756
H-Index - 81
eISSN - 1365-2052
pISSN - 0268-9146
DOI - 10.1111/j.1365-2052.2012.02360.x
Subject(s) - quantitative trait locus , epistasis , biology , genetics , inclusive composite interval mapping , candidate gene , family based qtl mapping , allele , gene mapping , gene , chromosome
Summary The aim of this study was to map QTL for meat quality traits in three connected porcine F 2 crosses comprising around 1000 individuals. The three crosses were derived from the founder breeds C hinese M eishan, E uropean W ild B oar and P ietrain. The animals were genotyped genomewide for approximately 250 genetic markers, mostly microsatellites. They were phenotyped for seven meat quality traits (p H at 45 min and 24 h after slaughter, conductivity at 45 min and 24 h after slaughter, meat colour, drip loss and rigour). QTL mapping was conducted using a two‐step procedure. In the first step, the QTL were mapped using a multi‐ QTL multi‐allele model that was tailored to analyse multiple connected F 2 crosses. It considered additive, dominance and imprinting effects. The major gene RYR1 :g.1843 C > T affecting the meat quality on SSC 6 was included as a cofactor in the model. The mapped QTL were tested for pairwise epistatic effects in the second step. All possible epistatic effects between additive, dominant and imprinting effects were considered, leading to nine orthogonal forms of epistasis. Numerous QTL were found. The most interesting chromosome was SSC 6. Not all genetic variance of meat quality was explained by RYR1 :g.1843 C > T . A small confidence interval was obtained, which facilitated the identification of candidate genes underlying the QTL . Epistasis was significant for the pairwise QTL on SSC 12 and SSC 14 for p H 24 and for the QTL on SSC 2 and SSC 5 for rigour. Some evidence for additional pairwise epistatic effects was found, although not significant. Imprinting was involved in epistasis.