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 VE = {VF1 + (VP1+ VP2)/2}/2 = {110 + (110 + 200)/2}/2 = 132.5 VP = 210 Vg = VP – VE = 210 – 132.5 = 77.5 Heritiablity H2 = Vg /VP = 77.5 / 210 = 0.369 Generation Variance P1 200 P2 110 F1 110 F2 210.