Question

During his studies on genes in Drosophila that were sex-linked TH.Morgan found F₂ - population phenotypic ratios deviated from expected 9 : 3 : 3 : 1. Explain the conclusion he arrived at.

Answer 1

(i) Linkage, genes on the same chromosome were either closely associated or far apart 

(ii) Higher Percentage of parental combination and fewer percentage of recombinants are observed when two genes are located very close / tightly linked on the same chromosome. 

(iii) Higher percentage of recombinants and fewer percentage of parental combinations are observed when two genes are located far apart / loosely / Linked on the same chromosome.