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Out of context: Reply #9526
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- Nairn0
I have to wait 'til sundown before I can go outside, in these thin-aired high-UV winter months¹.
The sun's just slipped behind the local tall building - time for lunch in Stoke in some chi-chi hole.
ta-ta, para
x¹:
Red hair is the rarest type of natural hair color in humans and the reasons for its occurrence are unclear. The pale skin associated with red hair may be of advantage in far-northern climates where sunlight is scarce. Studies by Bodmer and Cavalli-Sforza (1976) hypothesized that lighter skin pigmentation prevents rickets in colder latitudes by encouraging higher levels of Vitamin D production and also allows the individual to retain heat better than someone with darker skin. Rees (2004) suggested that the vividness and rarity of red hair may lead to it becoming desirable in a partner and therefore it could become more common through sexual selection.Harding et al (2000) proposed that red hair was not the result of positive selection but rather occurs due to a lack of negative selection. In Africa, for example, red hair is selected against because high levels of sun would be harmful towards fair skin. However, in Northern Europe this does not happen and so redheads can occur through genetic drift.