Fig. 1
Pedigrees depict the three types of sibling groups and parental genetic contributions to sons’ social functioning. Paternal and maternal genetic contribution was estimated as σ2g/σ2P, or the proportion of phenotypic variance attributable to genetic variance. Sons are depicted by small blue squares, fathers by large blue squares, and mothers by large orange circles. a Non-social behavior for paternal and maternal half-siblings. b Non-social behavior for full-siblings. c Quantitative autistic-like traits for paternal and maternal half-siblings. Of the N = 24 full-siblings in panel b, the eldest in each pair is included in the half-sibling analysis in panel a. Of the N = 274 half-siblings in panel a, N = 175 are included in the analysis in panel c. Similarly, of the N = 194 half-siblings in panel c, N = 175 are included in the analysis in panel a. A selective paternal transmission effect was found for both social functioning measures