Dominant Health Dictionary

A term used in genetics to describe one of the ways in which a gene is passed from parent to offspring. Many characteristics are determined by a single pair of genes, 1 of each pair being inherited from each parent. A dominant gene overrides an equivalent recessive gene. For example, the gene for brown eye colour is dominant, so if a child inherits the gene for brown eyes from 1 parent and the gene for blue eyes from the other, he or she will have brown eyes. Some genetic disorders are determined by a dominant gene. Examples include Marfan’s syndrome and Huntington’s disease. The child will have the disease if he or she inherits the gene from 1 or both parents.

adj. (in genetics) describing a gene (or its corresponding characteristic) whose effect is shown in the individual whether its *allele is the same or different. If the allele is different it is described as *recessive and its effect is masked. In genetic diseases showing autosomal dominant inheritance, the defective gene is dominant and will therefore be inherited by 50% of the offspring (of either sex) of a person with the disease. It will always be expressed in these offspring (since the normal allele inherited from the unaffected parent is recessive). —dominant n.