Polygenic Traits and Pleiotropy

Polygenic Traits and Pleiotropy

Author: Aaron Mullally

This lesson will explain what a polygenic trait is and give examples of polygenic and pleiotropy traits.

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Notes on "Polygenic Traits and Pleiotropy"


(00:00-00:53) Key Terms

(00:54-01:26) Polygenic Trait

(01:27-02:55) Continuing Variation

(02:56-05:20) Sickle-Cell Anemia

Source: Aaron M

  • Polygenic Trait

    A trait that is determined by several genes.

  • Continuous Variation

    Variation of a trait that shows up in a population of people, body height for instance.

  • Multifactorial Trait

    A gene that is partially controlled by genetics and partially controlled by the environment. For example, body height is genetic but nutrition growing up also influences height.

  • Penetrance

    The degree to which an inherited allele is expressed in the phenotype. An example would be achondroplastic dwarfism; if a person inherits the allele and it presents, they will be a dwarf.

  • Pleiotropy

    When one gene influences multiple phenotypic traits. Examples would be sickle-cell anemia and phenylketonuria (PKU).

  • Sickle-cell Anemia

    An example of pleiotropy, a person who inherits the mutated HBs gene will contract sickle-cell anemia which damages erythrocytes, the spleen and many other organs of the body.