IGCSEBiologyEdexcelBiology (Modular)Unit 2Revision Notes4. Reproduction & InheritanceInheritancePolygenic Inheritance

Polygenic Inheritance (Edexcel IGCSE Biology (Modular)): Revision Note

Exam code: 4XBI1

Lára Marie McIvor

Last updated

Edexcel Biology (Modular): Unit 2Edexcel Science (Double Award): BiologyEdexcel Biology

Polygenic Inheritance

  • Most characteristics are a result of multiple genes interacting, rather than a single gene

  • Characteristics that are controlled by more than one gene are described as being polygenic (poly = many)

  • Polygenic characteristics often show a wider range of phenotypes, rather than just two options

  • The inheritance of these polygenic characteristics is called polygenic inheritance 

  • Polygenic inheritance is difficult to show using simple genetic diagrams, due to the many possible combinations of alleles

  • Examples of polygenic inheritance:

    • Height in humans is controlled by several genes, each contributing to how tall a person becomes. This results in a continuous range of phenotypes, from very short to very tall

    • Skin colour and weight are other examples of polygenic inheritance

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    Lára Marie McIvor

    Author: Lára Marie McIvor

    Expertise: Biology, Psychology & Sociology Subject Lead

    Lára graduated from Oxford University in Biological Sciences and has now been a science tutor working in the UK for several years. Lára has a particular interest in the area of infectious disease and epidemiology, and enjoys creating original educational materials that develop confidence and facilitate learning.