The distribution of multiple DNA methylation profiles changed during differentiation by presenting an increased diversity with more hypermethylated and hypomethylated genes, and a modified landscape of gene methylation. During the undifferentiated/renewal state, the vast majority of genes (93%) were moderately methylated (between 0.4 and -0.4 log mean methylation, see definition in Method) (Figure 3A). During differentiation, a total of 1143 genes changed the methylation status, and, out of those, alcohol prevented the change of 272 genes (p <0.05). Among the 344 genes that were changed from moderate methylation during differentiation, 222 became hypermethylated and 122 hypomethylated. When the DRG stem cells were treated with alcohol during differentiation, 97 genes out of those 344 changes were prevented or reversed; 78 genes were prevented from hypermethylation, and 19 genes changed from hypomethylation back to moderate methylation status (Figure 3B).
