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

Polygenic Inheritance (Edexcel IGCSE Biology (Modular): Unit 2): Revision Note

Exam code: 4XBI1

Lára Marie McIvor

Written by: Lára Marie McIvor

Reviewed by: Lucy Kirkham

Updated on

Edexcel Biology (Modular): Unit 2Edexcel Science (Double Award) (Modular): Biology 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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Author
Reviewer
Lára Marie McIvor

Author: Lára Marie McIvor

Expertise: Content Creator

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.

Lucy Kirkham

Reviewer: Lucy Kirkham

Expertise: Content Creator

Lucy has been a passionate Maths teacher for over 12 years, teaching maths across the UK and abroad helping to engage, interest and develop confidence in the subject at all levels.Working as a Head of Department and then Director of Maths, Lucy has advised schools and academy trusts in both Scotland and the East Midlands, where her role was to support and coach teachers to improve Maths teaching for all.