Answer:
225 flies
Explanation:
Let gene for body colour : A
Let gene for eye type : B
Parent 1 : normal body and normal eyes = AABB
Parent 2: ebony body and eyeless = aabb
F1 : AABB X aabb = AaBb ( all have normal body and normal eye )
F1 progeny is self crossed given that the two genes are on different chromosomes which means they show independent assortment:
AaBb X AaBb =
A_B_ = normal body, normal eyes = 9
aaB_ = ebony body, normal eyes = 3
A_bb = normal body, eyeless = 3
aabb = ebony body, eyeless = 1
Hence the ratio is 9 : 3 : 3 : 1
Out of the 400 flies:
(9/16) * 400 = 225 flies have normal body colour and normal eyes
