CSPG4 and glioma: To address this question, we leveraged a genetic mouse model termed Mosaic Analysis with Double Markers (MADM),[7, 34] which we have previously used to mimic sporadic somatic mutagenesis in glioma patients (see also working scheme in Figure S5A, Supporting Information).[7] In the MADM‐Mutant model (Figure 4A), mitotic recombination mediated by the NG2‐Cre transgene enables pairs of GFP‐labeled mutant and tdTomato‐labeled wild‐type OPCs to be generated simultaneously from unlabeled heterozygous OPCs.