Partitioning the variance into variance explained by pedigree data and variance explained by SNP data showed that for both neuroticism and extraversion one third of the variance (14%) that was explained by pedigree data could be picked up by SNP similarity alone (analysis 4 in Supplementary Information Table S3). Further partitioning showed that the part of the variance that could be explained by SNP similarity was mainly due to variation detected from those individuals that are ‘unrelated' in the conventional (pedigree) sense, and much less so to variation in realized genetic similarity of related individuals around the expected (pedigree) values (analyses 5–7 in Supplementary Information Table S3). However, the s.e. of the estimates from realized similarity were large, as expected from theory and empirical studies.53, 54
