5 Out of 800 progeny of a threepoint testcross there were 16

5. Out of 800 progeny of a three-point testcross, there were 16 double crossover recombinants, whereas 80 had been expected on the basis of no interference. The interference is: A) There is no interference. B) 0.10 C) 0.20 D) 0.50 E) 0.80

Solution

Coefficient of coincidence measures interference in the form of chromosomal crossing overs during meiosis

Coefficient of coincidence = actual number of recombinations/

Expected number of recombinants

So 16/80= 1/5 = 0.2

Interference = 1- coefficient of coincidence

,= 1-0.2 = 0.8 is the answer