<< Back to glossary index

Definition

A type of allele where only one copy needs to be present for the phenotype to be expressed.

Use in clinical context

Individuals have two copies of each gene, with the exception of genes on the sex chromosomes in males, and both can contribute to an individual’s phenotype. For dominant alleles only one copy needs to be present for it to be expressed. In heterozygous individuals the dominant allele will be expressed over the recessive allele.

Last updated on 31st May, 2019