Number of Exchanges in Female and Male Meioses for 21q
| No. of exchanges | Female meioses | Male meioses | |||||
| observed | expected (Poisson) | expectedb (Laurie and Hulten 1985) | observed | expected (Poisson)[i] | |||
| 0 | 80 | 93 | 77 | 92 | 78 | ||
| 1 | 83 | 64 | 78 | 51 | 79 | ||
| 2+ | 23 | 29 | 5 | 17 | 3 | ||
| Total | 186 | 186 | 160 | 160 | 160 | ||
| χ2, 1 d.f. | 7.9 | 26.9 | 1.4 | ||||
| p-value | 0.005 | 2 × 10−7 | 0.244 | ||||
[i] Expected numbers of exchanges were computed assuming a null (Poisson) distribution of no interferences. bThe data were also compared with exchange frequency derived from empirical chiasma counts in human males (Laurie and Hulten 1985). Female meioses had a maximum of two exchanges, but males had one meiosis with three exchanges.