Also found in: Medical, Encyclopedia, Wikipedia.
Related to overdominance: Multiple alleles


The condition of a heterozygote having a phenotype that is more pronounced or better adapted than that of either homozygote.

o′ver·dom′i·nant adj.


excessive dominance
References in periodicals archive ?
Swamp Rats eat the rhizomes of sedges with the potential for overdominance such as Sandhill Swordsedge and Thatch Saw-sedge (author, pers.
A quantitative trait locus genome scan for porcine muscle fiber traits reveals overdominance and epistasis.
Theoretically, heterosis, also called hybrid vigour, can be expressed indirectly through higher horn growth rates, presumably due to increased heterozygosity for loci with overdominance (Lippman and Zamir 2006, Keller and Taylor 2010).
An excessive amount of heterozygotes in the initial cycles can be interpreted as overdominance. Heterozygote deficiency, in turn, may be due to genetic drift, likely resulting from the recombination of a limited number of individuals selected throughout the cycles; this drift effect could increase the probability of eliminating certain genotypes and consequently contribute to the predominance of certain genotypic combinations of the population (Cruz et al., 2011; Souza Junior, Geraldi, & Vencovsky, 2000), beyond those that favor crossing between related individuals and a resulting increase in inbreeding (Falconer & Mackay, 1996).
It has enjoyed sufficient oak exposure to provide smoothness and a butterscotch background without overdominance. Gentle, but zesty, tangerine based acidity sets off the wine's soft, pineapple, apricot and pear fruit beautifully.
In goats, it was reported that the INHA 651A/G polymorphism was a potential marker for the mean litter size of the second parity in Boer goats, which showed an overdominance effect (Wu et al., 2009).
Genetic studies on the Pacific abalone-I inbreeding and overdominance as evidenced by biochemical polymorphism in a wild population.
High heterozygosity of successful rampant clones may indicate the effect of overdominance, and the studied "Meshabash" clone is a good example of heterozygote superiority.
Based on single and two-locus QTL analysis, dominance [10], overdominance [3, 14, 15, 18, 19], epistasis [2, 16, 20], and accumulated effects [8, 12, 21-25] could be the major determinants of heterosis in rice.
The average degree of dominance as indicated by the ratio [([H.sub.1]/D).sup.1/2] suggested overdominance of this trait in both environments.
Inbreeding depression results from the expression of deleterious recessive alleles or from overdominance (Charnov, 1982; Charlesworth and Willis, 2009).
From shiny boardrooms to miners' informal shack housing, the economy's overdominance by finance is leading to economic choices that increase inequality and undermine long-term social and economic stability.