Fig. 2.

Validation of the Fetal Brain Clock in an independent fetal brain dataset. Shown are scatterplots comparing chronological age (x-axis; days post-conception (dpc)) against predicted epigenetic age (y-axis; days post-conception) calculated using A Fetal Brain Clock (FBC), B Horvath’s Multi Tissue Clock (MTC), C Knight’s Gestational Age Clock (GAC), and D Lee’s Control Placental Clock (CPC) on data from an independent validation dataset (n = 129, age range = 42–280 dpc). Two statistics were calculated to evaluate the precision of each DNAm clock: Pearson’s correlation coefficient (r) and the root mean squared error (RMSE). The dashed line in A indicates a chronological age of 185 dpc, which is the oldest age in the training dataset of the FBC