Ambidirectional dominance occurs in a situation where multiple gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

s influence a phenotype

Phenotype

A phenotype is an organism's observable characteristics or traits: such as its morphology, development, biochemical or physiological properties, behavior, and products of behavior...

 and dominance is in different directions depending on the gene. The opposite situation, where all genes show dominance in the same direction, is called directional dominance. According to Broadhurst, ambidirectional dominance is the result of stabilising selection

Stabilizing selection

-Description:Stabilizing or ambidirectional selection, , is a type of natural selection in which genetic diversity decreases as the population stabilizes on a particular trait value. This is probably the most common mechanism of action for natural selection...

 in the evolutionary past. Ambidirectional dominance has been found for exploratory behaviour

Exploration

Exploration is the act of searching or traveling around a terrain for the purpose of discovery of resources or information. Exploration occurs in all non-sessile animal species, including humans...

s in mice

Mouse

A mouse is a small mammal belonging to the order of rodents. The best known mouse species is the common house mouse . It is also a popular pet. In some places, certain kinds of field mice are also common. This rodent is eaten by large birds such as hawks and eagles...

 and Paradise fish

Paradise fish

Paradise fish or paradise gouramis are small freshwater labyrinth fish found in ditches and paddy fields in East Asia, ranging from the Korean Peninsula to Northern Vietnam....

.