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redheadadjective Referring to red (ginger) hair or a person with same.
noun A person with orange-red hair colour, or the hair itself, which is seen in 1–2% of the entire human population, 2–6% in Europeans, and 13% of Scots.
Red hair is an autosomal recessive phenotype inherited when both patents have specific codon changes on MC1R, the melanocortin-1 receptor gene—aka, melanocyte-stimulating hormone receptor (MSHR). A ginger child can be born to non-ginger parents. The increase of red hair in northern Europe relative to Africa, where there is natural selection against light-coloured skin, has been attributed to a lack of negative selection, to genetic drift and possibly to sexual selection. Data suggest that gingers differ from non-gingers in sensitivity to pain and anaesthetics, which has been attributed to molecular cross talk between melanin-stimulating hormone (MSH) and pro-opiomelanocortin (POMC) and their respective receptors.