Table 1.
Results for a ‘classic’ animal model of female age at first birth (AFB) in Swiss women (n = 6435), in which the potential for indirect genetic effects via the spouse is ignored. Birth year is included as a fixed covariate to control for a secular change in phenotypic expression over the study period and is mean-centred. Parish cohort is defined as the parish-specific decade in which the individual was born. Wife's family represents the natal family of the focal individual. The effect estimates are the point estimates ± standard error. Fixed and random effects were tested via z scores or χ2 scores, respectively.
| effect estimate | estimate relative to VP | z/χ2 | p | |
|---|---|---|---|---|
| fixed effects | ||||
| birth year | −8.2 × 10−3 ± 1.8 × 10−3 | — | −4.64 | <0.001 |
| (birth year)2 | 1.8 × 10−6 ± 1.3 × 10−5 | — | 0.14 | 0.886 |
| random effects | ||||
| wife's parish cohort | 1.3 ± 0.3 | 0.052 ± 0.010 | 115 | <0.001 |
| wife's family | 1.5 ± 0.5 | 0.063 ± 0.021 | 9.42 | 0.001 |
| additive genetic (wife) | 3.1 ± 0.7 | 0.130 ± 0.030 | 25.8 | <0.001 |
| residual | 18.3 ± 0.8 | 0.755 ± 0.033 | — | — |