In corn the leaf shine gene has two alleles g glossy determi

In corn, the leaf shine gene has two alleles g (glossy) determining glossy leaves, and G (dull); The ear branching gene has two alleles; the b allele (branched), determining branching of ears and the B allele (normal allele). When a plant heterozygous for each of these alleles was testcrossed, the progeny consisted of the following phenotypes with the numbers of each indicated.

dull, normal                 23

dull, branched              188   

glossy, normal             172

glossy, branched         17   

What is the distance between the leaf shine gene and the ear branching gene?

Solution

Answer:

Test cross--- GgBb (dull, normal) X ggbb (glossy, brandched)

Parental combinations= dull, branched & glossy, normal

Recombinants = dull, normal and glossy, branched

% of recombination frequency = distance between the genes(map units)

Recombinants = 40

Total = 400

Recombination frequency -= 40/400 * 100= 10%

Distance between the genes= 10 map units