Recessive

A term used in genetics to describe one of the ways by 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 recessive gene is overridden by an equivalent dominant gene. For example, the gene for blue eye colour is recessive; therefore, if a child inherits the gene for brown eyes from 1 parent and the gene for blue eyes from the other, the “blue eye” gene is overridden by the “brown eye” gene, and the child has brown eyes. The child must inherit the recessive blue eye gene from both parents in order to have blue eyes. Many genetic disorders are determined by a recessive gene. Examples include cystic fibrosis and sickle cell anaemia. The child will only have the disease if he or she inherits the gene from both parents.