Definition of Homozygosity

Homozygosity: The state of possessing two identical forms of a particular gene, one inherited from each parent.

For example, a girl who is homozygous for cystic fibrosis (CF) received the cystic fibrosis gene from both of her parents and therefore she has cystic fibrosis.

(A) heterozygote (possesses of two different forms of a particular gene, one inherited from each parent. For example, the father and mother of a cystic fibrosis child are heterozygotes for cystic fibrosis (CF). Each carries one normal gene and one cystic fibrosis gene but has no signs or symptoms of the disease.