21 SNPs at 131 age centers (ages 12 through 25 at 0.1 year intervals) were calculated. This provides effect size matrices of size 36 × 21 for each age center. The methods used to obtain the results are described in detail in Chorlian et al. (2017) and in Section 8.2. Much of the analysis was developed as an adaptation of the methods of a gene expression study of brain development in rats by Stead and colleagues (Stead et al., 2006). The key analogy is between the level of gene expression and the effect size of genotypic variants; more details can be found in 8.1.
