In a certain species of sea slug green body color A is reces

In a certain species of sea slug, green body color (A) is recessive to blue body color (B). and having a poisonous sting (St) is dominant to being non-poisonous (st). The genes for body color and poison arc located on the same chromosome. Previous mapping experiments have shown they are separated by 32.6 cM. A non-poisonous, green sea slug is crossed to a sea slug that is homozgous for both dominant traits. The FI are then crossed with non-poisonous, green sea slugs. What phenotypes and phenotypic proportions arc expected in the progeny of this cross?

Solution

Green, non poisonous    *   Blue, Poisonous
     (bb stst)                     (BB StSt)

F1              BbStst (Blue, poisonous)

At the distance of 32.6cM the probability of recombination occurs at 30%

    Blue, poisonous      *    Green, non poisonous        Test cross
        (Bb Stst)                    (bb stst)        

Gametes B b St st          b   b   st   st

	BSt	Bst	bSt	bst
bst	BbStst	Bbstst	bbStst	bbstst
Phenotype	Blue, poisionous	Blue, non poisonous	Green, poisonous	Green, non poisonous
Proportion	1	1	1	1