obligate heterozygote

Full Definition

An obligate heterozygote is an individual who, based on family history and pedigree analysis, must carry one copy of a specific allele, typically a recessive mutation. This determination is made through logical deduction when the individual has affected offspring or parents, making it impossible for them to be homozygous normal. In reproductive genetics, identifying obligate heterozygotes is crucial for accurate risk assessment and genetic counseling, particularly for autosomal recessive conditions where both parents must be carriers for the condition to manifest in offspring.

Usage

Usage note: Distinguish from 'carrier' which may be uncertain without genetic testing.

In Context

• "The mother of two affected children is an obligate heterozygote for the recessive mutation." — Genetic counseling report
• "Pedigree analysis revealed that both grandparents were obligate heterozygotes for the familial condition." — Family history documentation