Consequences of Epistasis on Growth in an Erhualian × White Duroc Pig Cross

Abstract

Epistasis describes an interaction between the effects of loci. We included epistasis in quantitative trait locus (QTL) mapping of growth at a series of ages in a cross of a Chinese pig breed, Erhualian, with a commercial line, White Duroc. Erhualian pigs have much lower growth rates than White Duroc. We improved a method for genomewide testing of epistasis and present a clear analysis workflow. We also suggest a new approach for interpreting epistasis results where significant additive and dominance effects of a locus in specific backgrounds are determined. In total, seventeen QTL were found and eleven showed epistasis. Loci on chromosomes 2, 3, 4 and 7 were highlighted as affecting growth at more than one age or forming an interaction network. Epistasis resulted in both the QTL on chromosomes 3 and 7 having effects in opposite directions. We believe it is the first time for the chromosome 7 locus that an allele from a Chinese breed has been found to decrease growth. The consequences of epistasis were diverse. Results were impacted by using growth rather than body weight as the phenotype and by correcting for an effect of mother. Epistasis made a considerable contribution to growth in this population and modelling epistasis was important for accurately determining QTL effects.

Genome-Wide Epistatic Interaction Networks Affecting Feed Efficiency in Duroc and Landrace Pigs

“…Epistatic interactions between genes for some quantitative traits, such as meat quality (Ovilo et al, 2002;Duthie et al, 2011a), carcass (Duthie et al, 2010), reproductive traits (Bidanel, 1993;Rodríguez et al, 2005;Noguera et al, 2009), growth (Crooks and Guo, 2017), and muscle fiber traits (Estellé et al, 2008) have been reported for pigs. These findings shed light on the different interactions underlying the genomic regulation in several traits.…”

Epistatic regulation of growth in Atlantic salmon revealed: a QTL study performed on the domesticated-wild interface

“…However, and to the best of our knowledge, this is the first empirical study to reveal epistatic regulation of a quantitative trait in Atlantic salmon. Epistasis-influences on growth have been documented in other animals such as mice [10], chicken [51] and pigs [52]. The documentation of epistasis as a genetic basis for quantitative trait variation in Atlantic salmon could have implications for selective breeding programs; a topic that has been debated in both MAS [53] and GS [54].…”