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Hair Color: Traits and Genes. KT Leitl. Basic Facts of Human Hair. Genes in hair color aren’t fully established. Theory – At least two gene pairs control human hair color Two pigments for hair color: Eumelanin and Pheomelanin. Eumelanin.
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Hair Color: Traits and Genes KT Leitl
Basic Facts of Human Hair • Genes in hair color aren’t fully established. • Theory – At least two gene pairs control human hair color • Two pigments for hair color: Eumelanin and Pheomelanin
Eumelanin • Eumelanin – The two subtypes determine the darkness • Black – High counts lead to blacker hair, lower counts result in gray hair • Brown
Pheomelanin Phenotypes Brown/Blonde Brown – Dominant allele Blonde – Recessive allele Non-red/Red Non-red – Dominant (suppresses pheomelanin Red - Reccessive • Pheomelanin - is generally makes red
Brown Hair (Brunettes) • Higher levels of (brown) eumelanin • Lower levels of pheomelanin • Medium to thick hairstrands
Black Hair • Most common • Ranging from soft black, blue-black, and jet black • Lots of eumelanin • Less dense color
Blonde Hair • Platinum blonde, dark blonde, strawberry blonde (most rare and contains the most pheomelanin) • Only small amounts of pheomelanin and eumelanin (more creates ash blonde) • Most blondes get darker with age
Auburn Hair • Ranges from light to dark red-brown • Eumelanin (brown) • Pheomelanin (red)
Chestnut Hair • Red-ish shade of brown • Darker than auburn
Red Hair • Least common • Light strawberry, titan vivid orange, copper, “true red” (least common) • Caused by Mc1r (recessive) • 67% pheomelanin • Lowest levels of eumelanin • Most common in Scotland (13% are, 40% carry the recessive gene)
Grey and White Hair • No actual pigment • Clear hair • Lack of pigment and melanin • Color based on light reflection • Generally in people of age • As early as ten
Gender In Hair Men Women Red and blond hair • Generally black of dark hair
Works Cited • En.wikipedia.org/wiki/Human_hair_color • Google images