Morphology of epidermal melanocytes in different stages of mitosis

The structural changes which take place in epidermal melanocytes during mitosis have been investigated in serial sections of ear skin of C57Bl mice. Melanocytes were DOPA-positive and contained melanosomes in all stages of the mitotic cycle. They retracted their dendrites in prophase so that metaphase cells assumed an almost spherical shape. Signs of new dendrite growth were seen in late telophase and fully developed dendrites first after the division was completed. It is concluded that new epidermal melanocytes are formed in the mouse by division of already differentiated melanocytes.