Table 2.
Predicted handedness in families and in monozygotic twins for the single-locus model (N loci = 1) and multilocus modelsa
| Percent left-handedness by parental phenotype |
Percent concordance and discordance in monozygotic twins |
||||||
|---|---|---|---|---|---|---|---|
| N loci | ci | R × R | R × L | L × L | R – R | R – L | L – L |
| 1 | 0.20000 | 7.82% | 18.90% | 30.63% | 83.00% | 14.00% | 3.00% |
| (7.78%) | (18.89%) | (30.00%) | (83.00%) | (14.00%) | (3.00%) | ||
| 2 | 0.11110 | 8.15% | 17.74% | 25.56% | 82.80% | 14.40% | 2.83% |
| 3 | 0.07715 | 8.19% | 17.24% | 24.17% | 82.74% | 14.55% | 2.71% |
| 4 | 0.05916 | 8.29% | 17.01% | 22.88% | 82.70% | 14.64% | 2.66% |
| 5 | 0.04780 | 8.35% | 16.79% | 22.60% | 82.65% | 14.69% | 2.66% |
| 10 | 0.02473 | 8.38% | 16.45% | 21.86% | 82.60% | 14.85% | 2.55% |
| 20 | 0.01256 | 8.46% | 16.50% | 21.53% | 82.50% | 14.95% | 2.55% |
| 50 | 0.00507 | 8.52% | 16.09% | 20.02% | 82.51% | 14.97% | 2.53% |
| 100 | 0.00254 | 8.48% | 16.10% | 20.28% | 82.52% | 14.98% | 2.49% |
| 200 | 0.00127 | 8.55% | 16.30% | 20.83% | 82.39% | 15.09% | 2.51% |
| 500 | 0.00051 | 8.56% | 16.12% | 21.06% | 82.54% | 14.91% | 2.55% |
| 1000 | 0.00026 | 8.52% | 16.26% | 20.29% | 82.46% | 15.03% | 2.51% |
| Approximate CI | ±0.05% | ±0.07% | ±0.08% | ±0.08% | ±0.07% | ±0.03% | |
a
Results are from 1,000,000 Monte Carlo simulations for p(L) = 10%, with the exception of values in parentheses for N loci = 1, which are analytic solutions. For Monte Carlo calculations, approximate 95% confidence intervals (CI) are shown in the last row.