4-genetics ahl - polygene (by peter)

Polygenic Inheritance

Peter Baek

Assessment Statements

• 10.3.1• Define polygenic inheritance.• 10.3.2• Explain that polygenic inheritance can

contribute to continuous variation using two examples, one of which must be human skin colour.

Define polygenic inheritance.

• A single characteristic controlled by multiple genes

• polygenic inheritance gives continuous variations in the phenotype

Explain that polygenic inheritance can contribute to continuous variation using two examples, one of which must be human skin

colour.

• - Skin color is determined by the concentration of melanin. The darker the skin the greater protection from the sun.

• Skin color is controlled by four separate genes each with different alleles.

Explain that polygenic inheritance can contribute to continuous variation using two examples, one of which must be human skin

colour.

• Two allelesContributing- Add to the phenotypeNon-Contributing- do not add to the phenotypeIf genes are assumed that they are not linked

Continuous Variation in the Phenotype

Continuous Variation

• Think of more examples of Continuous Variation

•

Try it yourself

Ratio

Wheat Color, Eye Color

• How many genotypes and phenotype of two genes with two alleles will be possible?

• 9!