Use the preamble below to answer Questions 27 and28
In the fruit fly Drosophila melanogaster, red eye colour (R) isdominant to white eye colour (r). A
student wishes to perform a test cross to determine whether afemale red eyed fruit fly is
homozygous or heterozygous for the eye colour. The student matesthe female fruit fly with a red
eye coloured male and studies the offspring, which are 100% redeye. The student concludes that
the genotype of the female fruit fly Drosophila melanogaster is\"RR\".
27. What mistake(s) did the student make if any? Briefly explain inbullet points. [5 Marks]
28. Suggest the best way by which a breeder could successfullymaintain a supply of red eye
Drosophila melanogaster of the variety that is heterozygous for eyecolour. [5 Marks]
Use the preamble below to answer Questions 29 and 30
In a breed of cattle, rough coat is dominant over smooth, and blackcoat is codominant to red. What
do the following statements mean?
29. The loci of the two pair of genes concerned are on the samepair of chromosomes (assuming
no crossing over). [5 Marks]
30. The loci of the two pair of genes concerned are on differentpairs of chromosomes.
[5 Marks]
