Skip to content
    Biology A-Level

    codominance

    What codominance means in Biology A-Level, as defined for AQA.

    Definition of codominance

    Check what you remember

    Read the wording for your board, then hide it and explain codominance in your own words. Rough notes are fine. This is a self-check, with no mark or grade.

    Reference: AQA

    Both alleles are expressed in the heterozygote, producing a third phenotype, and both proteins are made so both characteristics appear rather than an average.
    AQA · Inheritance (A-level only) (study guide)

    Topics that use codominance

    Related terms

    Using codominance in the exam

    Check the command word and mark scheme for your exact question. After comparing your explanation with the reference, use the term in an answer on the linked topic. This practice does not predict an exam mark.

    Practise Biology questions

    Create a free account to answer exam-style questions on this topic and get feedback on your answers.

    Start free

    A week of Premium from your first lesson · Then the free plan continues · No card, no charge

    All Biology A-Level terms