Question

What is the expected phenotypic ratio in the F2 generation for human skin colour inheritance with three gene pairs?

Options

• 1:2:1

• 3:1:2

• 1:6:15:20:15:6:1

• 1:1:1:1

Answer 1

The expected phenotypic distribution in the F2 generation for human skin colour with three contributing gene pairs is 1:6:15:20:15:6:1. This ratio demonstrates that intermediate phenotypes (the middle values of 20, 15, and 15) are most common, while extreme phenotypes (1 and 1) are least common, reflecting the continuous variation characteristic of polygenic inheritance.