Illustration of skin tanning under the effect of the sun ultraviolet rays. Melanocytes (green cells in the epidermis) produce melanin, a pigment that absorbs ultraviolet rays. Melanin travels in melanosomes that migrate towards keratinocytes, placing themselves on their nucleus to protect their DNA and prevent genetic mutations due to the sun. Melanin makes the skin browner, thicker and more resistant to ultraviolet rays.