Question

There are three genes that you are tracking on a fruit fly:

 Gene ‘r’ that results in the phenotype of red body colour

 Gene ‘t’ for the phenotype of transparent wings

 Gene ‘b’ for the phenotype of black coloured eyes.

You cross breed fruit flies with the above mentioned genes and observe the following:

 When red body fruit flies are cross bred with transparent winged fruit flies, 2400 offspring were produced. Out of the 2400 offspring, 912 are recombinants.

 When transparent winged fruit flies were cross bred with black eyed fruit flies, 2610 offspring were produced. Out of the 2610 offspring, 260 are recombinants.

 When red body fruit flies are cross bred with black eyed fruit flies, 2300 offspring were produced. Out of the 2300 offspring, 331 were found to be recombinants

a. Calculate the distance between each gene in relative map units (to 1dp). (3 marks)

b. In the image below, indicate the locations of gene ‘r’, gene ‘t’ and gene ‘b’ in the blank boxes. (3 marks)