TABLE 10

Simulation results of mapping epistatic QTL in the F2 population

Without epistasisaWith epistasisb
QAQBQAQB
Power1.0000.2381.0000.500
Position51.25 (7.73)89.63 (24.19)50.99 (7.95)90.46 (18.67)
0.0125 (0.3701)0.0091 (0.3635)
a2.9941 (0.5696)1.8567 (0.4196)2.9658 (0.5700)1.3314 (0.6368)
d0.9816 (0.9018)1.0024 (0.8697)
iaa1.9897 (0.9948)
σ224.26 (3.29)24.02 (3.50)
h20.2158 (0.0445)0.2257 (0.0494)
  • Numbers in parentheses are standard deviations. The critical values for claiming significance are χ21,0.05/20 = 9.14 and χ22,0.05/20 = 11.98. Two unlinked QTL, QA and QB, are simulated on the chromosomes with 11 15-cM equally spaced markers. QA is placed at 52 cM with additive effect 3 and dominance effect 1. QB is placed at 93 cM with additive effect 1 (a1 = 3, d1 = 1, a2 = 1; VA/VG = 76%, VB/VG = 16%). The mean is 0, and the additive-by-additive epistatic effect is 2 (μ = 0, iaa = 2; Vi/VG = 16%). The heritability is 0.2 (h2 = 0.2, σ2 = 25). Th sample size is 200 and the simulated replicates are 500.

  • a QTL mapping with epistasis ignored.

  • b QTL mapping with epistasis taken into account.