A XwmXwm female was mated to a XwmY male Out of 1000 total F

A X^w+m+X^wm female was mated to a X^wmY male. Out of 1000 total F₁ progeny there were 230 flies that were otherwise wild type with white eyes and 240 flies that were otherwise wild type with miniature wings. What is the distance between the genes for eye color and wing length?

A. 47 map units

B. 24 map units

C. 53 map units

D. 23 map units

Solution

The relative distance between the genes (gene distance) can be measured from the recombination frequency. The percentage of recombination or crossing over is equivalent to map unit or centimorgan (cM). 1 map unit or 1 cM is equal to 1 % recombination. The distance between the genes or map distance is given by the equation:

(No: of recombinant offspring/Total no: of offspring) X 100

Here, the total no : of offspring = 1000

No: of recombinant progeny = 1000- (parental /wild types)

                                             = 1000- (230+240) =530.

Recombination frequency = (530/1000) x 100 = 53

The answer is C.53 map units.