Figure 4. Keratinocyte differentiation does not drive epigenetic ageing. (A) Phase contrast image of a primary keratinocyte colony grown in the presence of irradiated J2-3T3 feeder cells in RG medium. The keratinocyte colony is demarcated within the blue boarder and proliferating or differentiating keratinocytes are indicated. Cells external of the boarder are irradiated 3T3-J2 feeder cells. (B) Comparison of epigenetic aging between primary keratinocytes grown in CnT-07 media (CnT) and RG media (RG).