Atopic Dermatitis: a Short Summary
- 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: http://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
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