Question

How did T.H. Morgan disprove Mendelian dihybrid F₂ phenotypic ratio of 9 : 3 : 3 : 1? Explain giving reasons.

Answer 1

Morgan studied sex-linked genes in Drosophila by conducting many dihybrid crossings. He discovered that the F₂ ratio differed from the 9 : 3 : 3 : 1 ratio, which is what is expected when the two genes are independent, indicating that the two genes did not segregate independently of one another.