these genes reflect decreasing progenitor cell division. Conversely, module C22 is enriched in newly generated postmitotic neurons of the CP, and increases with age (Fig. 3b, lower left). Importantly given the small sample size, this temporal patterning in C38 and C22 is corroborated by RNA-seq data from a larger timeseries of cortical development contained in the BrainSpan resource (Extended Data Fig. 5). Interestingly, genes in module C22 significantly overlap genes showing altered expression in postnatal human brains of patients affected by autism38. This suggests involvement of autism risk factors in early development of excitatory cortical neurons, consistent with other recent studies39,40.
