Question

If flies that are heterozygous for all three traits are crossed with flies that are homozygous recessive for all three traits, what proportion of the offspring would you expect to be heterozygous for all three traits?

Answer 1

1/8

Step-by-step explanation:

Let's suppose that the heterozygous flies have genotype AaBbCc (heterozygous for three traits) and the homozygous recessive files have the genotype "aabbcc".

The total probability of having heterozygous progeny for all three traits can be calculated by separately calculating the frequency of the heterozygous progeny for each trait.

Aa x aa= 1/2 Aa: 1/2 aa

Bbx bb= 1/2 Bb: 1/2 bb

Cc x cc= 1/2 Cc: 1/2 cc

Therefore, the probability of having progeny that is heterozygous for all three genetic loci (AaBbCc) will be= 1/2 Aa x 1/2 Bb x 1/2 CCc= 1/8 AaBbCc