In Drosophila , the recessive pr and cn mutations cause brown and bright-red eye
ID: 275912 • Letter: I
Question
In Drosophila, the recessive pr and cn mutations cause brown and bright-red eyes, respectively (wild-type flies have brick-red eyes). The double mutant pr cn combination has orange eyes. A female who has wild-type eyes is crossed to an orange-eyed male. Their progeny have the following distribution of eye colors:
Which classes are the parental types?
wild-type and brown
brown and bright-red
bright-red and orange
wild-type and orange
There is no way to determine this.
wild-type 8 brown 241 bright-red 239 orange 12 500Explanation / Answer
The offpsring ratio is not in 1:1:1:1 ratio which indicates that these two genes are linked. Due to the linkage phenomenon, the parental types will be high in number and where as the recombinants are low in number.
So, the high number phenotypes here i.e. brown with 241 and bright red with 239, these indicates the parental categoreis.
Hence the answer is brown and bright-red