The role of epistasis in the manifestation of heterosis: a systems-oriented approach

Melchinger, A E; Utz, H F; Piepho, H-P; Zeng, Z-B; Schön, C C (2007). The role of epistasis in the manifestation of heterosis: a systems-oriented approach. Genetics, 177(3), pp. 1815-25. Bethesda, Md.: Genetics Society of America 10.1534/genetics.107.077537

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Heterosis is widely used in breeding, but the genetic basis of this biological phenomenon has not been elucidated. We postulate that additive and dominance genetic effects as well as two-locus interactions estimated in classical QTL analyses are not sufficient for quantifying the contributions of QTL to heterosis. A general theoretical framework for determining the contributions of different types of genetic effects to heterosis was developed. Additive x additive epistatic interactions of individual loci with the entire genetic background were identified as a major component of midparent heterosis. On the basis of these findings we defined a new type of heterotic effect denoted as augmented dominance effect di* that comprises the dominance effect at each QTL minus half the sum of additive x additive interactions with all other QTL. We demonstrate that genotypic expectations of QTL effects obtained from analyses with the design III using testcrosses of recombinant inbred lines and composite-interval mapping precisely equal genotypic expectations of midparent heterosis, thus identifying genomic regions relevant for expression of heterosis. The theory for QTL mapping of multiple traits is extended to the simultaneous mapping of newly defined genetic effects to improve the power of QTL detection and distinguish between dominance and overdominance.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > Service Sector > Institute of Legal Medicine

UniBE Contributor:

Schön, Corinna






Genetics Society of America




Factscience Import

Date Deposited:

04 Oct 2013 14:56

Last Modified:

04 May 2014 23:16

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URI: (FactScience: 45126)

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