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The presence of two identical alleles within an individual.

Use in clinical context

Individuals have two copies of genes on the autosomes (and in females on the X chromosomes), in homozygous individuals (homozygotes) both copies of the allele are identical. Homozygous individuals will always pass their allele onto any children.

Recessive alleles require two copies to be expressed so individuals expressing recessive phenotypes are homozygous for the allele.

Related terms

Allele | Autosomes | Gene | Recessive allele

Last updated on 29th May, 2019