Skin Evolutionary Theories in Early Mankind (Applied Darwinian principles) and the importance of MC1R

• Characteristics of the skin in the direct predecessor of mankind (homo (neandertalis…)):
  • functional hairlessness
  • increased density of eccrine glands
  • persistence of hair follicular units

• 1 million years ago, the predecessors of mankind, the skin (in addition to becoming hairless became) darkly pigmented and MC1R became invariant
• It was been shown that in that skin; High levels of melanocortins were found  in UV irradiated skin

• The role of MC1R
  • induction of protective pigmentation
  • activation of the DNA damage response

• So the skin of the direct predecessors of mankind was hairless, darkly pigmented and was the primary interface with the environment

• What were the selective pressures according to Darwinian principles:
  • increased barrier functions (reduced pH)
  • protection against Ultraviolet radiation

• Further differentiation into subgroup skin subtypes (caucasian, asian, arabic skin…) was by selective evolution adapted to migration: the skin is the result of a biocultural selective adaptation and is a combination of lightly follicular density, with a more or less pigmented skin responding more or less to UV radiation

Further reading: https://www.globale-dermatologie.com/en/skin-color-regulation-by-genes.html#.VAk3-0jbw4Y

Contributors

Dr Christophe Hsu – dermatologist. Geneva, Switzerland

Source of Information. Jablonski N. Natural Selection  and the Natural Evolution of Skin Color Phenotypes. 2014 (09) – International Pigment Cell Conference (IPCC). Singapore