Principles of Genetics and Breeding (1+1)

2.1.13 Homozygous

2.1.13 Homozygous and Heterozygous

If the copy of the gene that a fish inherits from its father is the same as the copy that it inherits from its mother, that gene is an identical pair of alleles, and the fish is said to be “homozygous” at that locus.

If the copy of the gene that a fish inherits from its father is different from the copy that it inherits from its mother, the gene is a non-identical pair of alleles, and that fish is said to be “heterozygous” at that locus.

Consequently, every gene can exist in one of two genotypic states; homozygous (identical pair of alleles) and heterozygous (non identical pair of alleles).