The results for height and BMI seem to be very different. For height, we identified 36 loci with multiple associated SNPs, whereas, for BMI, we did not find any such loci. It seems unlikely that this large difference can be entirely explained by the greater power to detect associations with height compared to BMI because of the greater heritability of height. The narrow-sense heritability for height is estimated to be ~80% by pedigree analyses22, and the heritability for BMI is ~40–60% (refs. 23,24). If we assume the heritability of BMI is 50%, then 4% (2%/50%) of narrow-sense heritability for BMI has been explained by GWAS4, a much lower proportion than that for height, which is approximately 12.5% (10%/80%)3. When considering all the SNPs simultaneously, 32% (16%/50%) of narrow-sense heritability for BMI can be captured by all common SNPs using the whole-genome estimation approach we recently developed, which is also lower than the corresponding explained heritability for height (~56%)14,18. In a previous analysis partitioning genetic variance onto individual chromosomes, the variance explained by each chromosome showed a strong linear relationship with
