Human pigmentation: A side effect adapted from a primitive organism's survival, acting through cell attachment with an affinity for the keratinocyte and for elastin: Part I

Abstract

Pigmentation featured millions of years ago and perhaps began with an amoeba frightening off a predator with some agent such as dopamine to prevent its attachment for phagocytosis by an enemy. This paper suggests that the environmental forces of grip and stick deserve greater emphasis and that mechanical forces involved in grip and stick or release from attachment, all point to control of proteases underlying pigmentation. There is an affinity for elastin as a pathway for melanin to exit its peripheral location in the epidermis into lymphatics and play a humeral role in defense mechanisms. The hair follicle follows the epidermal-dermal pattern of behavior with an affinity for elastin, a controlling function of melanin and through the bulge, an influence of mechanical forces and control by protease inhibitors.

Keywords: Evolution; keratinocyte; melanocyte; pigmentation; skin color.

Figure 1

The melanocyte's affinity for the keratinocyte and for elastin has much to do with grip and stick by the employment and inhibition of proteases. (1) Melanocyte inoculates keratinocytes with melanosomes and like many cells derived from the neural crest determines organ shape and relationships. (2) Melanocyte lyses epithelial basement lamina and uses elastin to guide it to the Lymphatic. (3) Basal keratinocytes lose grip and stick to the basal lamina and melanocyte while in mitosis and one is jostled out of contact with basement lamina. (4) Melanocyte contacting mid dermal horizontal elastin fibers take up a horizontal orientation