Regional heritability (FA and AD) varied with maturation status. Heritability was typically high in WM structures that mature earlier (Lee et al. 2009; Kochunov et al. 2010; Geng et al. 2012). However, at any age, heritability of FA in the corpus callosum was higher in the genu, which develops later than the splenium, but FA heritability for both genu and splenium decreased at the same rate over time (Brouwer et al. 2010; Kochunov et al. 2010; Brouwer et al. 2012).
