Ambidirectional dominance

Ambidirectional dominance occurs in a situation where multiple genes influence a phenotype and dominance is in different directions depending on the gene. For example, for gene A increased height is dominant, while for gene B decreased height is dominant. The opposite situation, where all genes show dominance in the same direction, is called directional dominance.{{cite book |editor1-first=JHF |editor1-last=van Abeelen |editor1-link=Hans van Abeelen |last1=Broadhurst |first1=PL |last2=Jinks |first2=JL |author-link2=John L. Jinks |title=The Genetics of Behaviour |chapter=What genetical architecture can tell us about the natural selection of behavioural traits |publisher=North Holland |location=Amsterdam| year=1974 |isbn=0-7204-7137-0 |pages=43–63 |oclc=1365968}} In the same example, for both genes A and B increased height is dominant. According to Broadhurst, ambidirectional dominance is the result of stabilising selection in the evolutionary past. Ambidirectional dominance has been found for exploratory behaviours in mice{{cite journal |author=Crusio WE |author-link=Wim Crusio |author2=van Abeelen JH |author2-link=Hans van Abeelen |title=The genetic architecture of behavioural responses to novelty in mice |journal=Heredity |volume=56 |issue= 1|pages=55–63 |date=February 1986 |pmid=3943979 |doi= 10.1038/hdy.1986.8|doi-access=free}}{{cite journal |vauthors=Crusio WE, Schwegler H, van Abeelen JH |title=Behavioral responses to novelty and structural variation of the hippocampus in mice. I. Quantitative-genetic analysis of behavior in the open-field |journal=Behavioural Brain Research |volume=32 |issue=1 |pages=75–80 |date=February 1989 |pmid=2930636 |doi=10.1016/S0166-4328(89)80074-9 |s2cid=675083}}{{cite journal |author=Crusio WE |title=Genetic dissection of mouse exploratory behaviour |journal=Behavioural Brain Research |volume=125 |issue=1–2 |pages=127–32 |date=November 2001 |pmid=11682103 |doi=10.1016/S0166-4328(01)00280-7 |s2cid=28031277 }} and paradise fish.{{cite journal |author=Gerlai R |author-link=Robert Gerlai |author2=Crusio WE |author3=Csányi V |title=Inheritance of species-specific behaviors in the paradise fish (Macropodus opercularis): a diallel study |journal=Behavior Genetics |volume=20 |issue=4 |pages=487–98 |date=July 1990 |pmid=2256892 |doi=10.1007/BF01067715 |s2cid=22641118}}