An inbred line of Drosophila will drink sugar water to which

An inbred line of Drosophila will drink sugar water to which small amounts of a bitter substance, quinine, has been added. The variance in quinine concentration tolerated is 200. They are crossed with a different inbred line whose variance in quinine concentration tolerated is 110. Their F_1S have a variance of 110, and their F_2S have a variance of 210. What is the heritability of this trait?

Solution

Generation

Variance

P1

200

P2

110

F1

110

F2

210

V_E = {V_F1 + (V_P1+ V_P2)/2}/2 = {110 + (110 + 200)/2}/2 = 132.5

V_P = 210

V_g = V_P – V_E = 210 – 132.5 = 77.5

Heritiablity H² = V_g /V_P = 77.5 / 210 = 0.369

Generation	Variance
P1	200
P2	110
F1	110
F2	210