Extended Data Fig. 1 |. Additional characterization of iAstrocytes.

a, Empirical cumulative distribution functions of the mean expression of genes (averaged across experimental replicates, n = 3 wells) with astrocyte-specific expression (astrocyte fidelity > 40) or without astrocyte specific expression (astrocyte fidelity < 40) in iAstrocytes vs astrocytes generated using the TCW et al. protocol¹⁶ (TCW astrocytes). Genome-wide astrocyte fidelity scores were obtained from Kelley et al. TPM: transcripts per million. b, Relative expression (z-scored) of the top 50 genes with the highest astrocyte fidelity scores from Kelley et al.115 (organized by hierarchical clustering, see Methods) in iAstrocytes vs. TCW astrocytes (n = 3 experimental replicates corresponding to heatmap rows). Genes with statistically significant differential expression (adjusted P value < 0.1) between iAstrocytes and TCW astrocytes are marked with asterisks; P values were calculated and adjusted for multiple testing (false-discovery rate method) using DESeq2 (two-sided Wald test; see Methods). c, Heatmap of log-scaled transcripts per million (TPM) values of NFIA transcripts in human primary astrocytes from Zhang et al.⁹² d, Representative images from immunostaining of GFAP in iAstrocytes cultured alone or with iNeurons (n = 3 wells). In each case, an entire field of view is displayed (left) next to magnified sections (all at same scale) containing representative astrocyte morphologies (right). Scale bars correspond to 60 μm.