Polygenic inheritance refers to a characteristic controlled by multiple genes. It results in continuous variations in phenotypes rather than discrete traits. For example, human skin color is determined by the concentration of melanin, which is influenced by four separate genes with different alleles, leading to a wide range of skin tones. Another example of polygenic inheritance producing continuous variation is wheat color, which is influenced by multiple genes.

1. Polygenic Inheritance
Peter Baek

2. 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.

3. Define polygenic inheritance.
• A single characteristic controlled by multiple
genes
• polygenic inheritance gives continuous
variations in the phenotype

4. 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.

5. Explain that polygenic inheritance can contribute to continuous
variation using two examples, one of which must be human skin
colour.
• Two alleles
Contributing- Add to the phenotype
Non-Contributing- do not add to the phenotype
If genes are assumed that they are not linked

6. Continuous Variation in the Phenotype

7. Continuous Variation
• Think of more examples of Continuous
Variation

8. Try it yourself

9. Ratio

10. Wheat Color, Eye Color
• How many genotypes and phenotype of two
genes with two alleles will be possible?
• 9!