<< Back to glossary index


A type of allele that when present on its own will not affect the individual. Two copies of the allele need to be present for the phenotype to be expressed.

Use in clinical context

With the exception of genes on the sex chromosomes, individuals have two copies of each gene and both can contribute to an individual’s phenotype. For recessive alleles both copies must be the same before they are expressed.

Last updated on 3rd June, 2019