Question

) When you count the F2 generation, you actually get 85 brown, winged fies, 728 black, winged flies, 712 brown, wingless flies, and 75 black, wingless flies. These results indicate that the body color and wing size are linked genes. . What are the phenotypes of the recombinant flies? (Hint: Refer back to the P generation flies in the first paragraph. Recombinant flies do not resemble the original P generation phenotypes.)

Answer 1

Specify the alleles associated with dominant phenotypes by uppercase letters and alleles associated with recessive phenotypes by lowercase letters. Assume the genes are not found on a sex chromosome. Indicate the color alleles as “B” and “b” the wing alleles by the letters “N” and “n”.

When we count the F2 generation, we actually get:

85 brown winged flies with genotype BbNn

728 black winged flies with genotype Bbnn

712 brown wingless flies with genotype bbNn

75 black wingless flies with genotype bbnn

Phenotypes of recombinant flies are:-

85 brown winged flies

75 black wingless flies

Recombination frequency = Number of Recombinants/total (100) = 85 +75/85 +75 + 728 + 712

=   0.1(100) = 10%