hair color: traits and genes
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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. - PowerPoint PPT PresentationTRANSCRIPT
Hair Color: Traits and GenesKT 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• Pheomelanin - is
generally makes red
Phenotypes• Brown/Blonde• Brown – Dominant allele• Blonde – Recessive allele
• Non-red/Red• Non-red – Dominant
(suppresses pheomelanin• Red - Reccessive
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• Generally black of dark
hair
Women• Red and blond hair
Works Cited• En.wikipedia.org/wiki/Human_hair_color • Google images