Genetics please answer A B and C of this question A B C Supp

Genetics: please answer A B and C of this question.

A)

B)

C)

Suppose a and b are recessive alleles of genes located 20 map units apart on chromosome 2 in Drosophila melanogaster. For the P generation, true-breeding a males are mated to true-breeding b females. In the F1 generation the heterozygous a b flies are crossed to each other. What proportion of F2 flies exhibit the recessive a phenotype and dominant phenotype for b in the next generation (i.e., are like the a males of the P generation)? You may wish to use a Punnet square again, but remember, there is no recombination in Drosophila males 0% 25% 5% 50% 10%

Solution

A. 50%

B. 25%

C. ab/ ++ x ab/++

Single trait Punnett Square tracks two alleles for each parent. The square has two rows and two columns.