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

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: The linkage relationships among the four mouse genes, A B, C, and D, are shown in the map below. What proportion of the eggs produced by a female mouse with genotype At/aB;D/cd will carry all the recessive alleles?

Solution

15. Interference = 1- coefficient of coincidence

where coefficient of coincidence = observed frequency/expected frequency

observed frequency=16 expected frequency=80

coefficient of coincidence = 16/80

interference =1-16/80=1-1/5

=1-0.2=0.8