KT Leitl

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 – 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

Higher levels of (brown) eumelanin Lower levels of pheomelanin Medium to thick hairstrands

Most common Ranging from soft black, blue-black, and jet black Lots of eumelanin Less dense color

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

Ranges from light to dark red-brown Eumelanin (brown) Pheomelanin (red)

Red-ish shade of brown Darker than auburn

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)

No actual pigment Clear hair Lack of pigment and melanin Color based on light reflection Generally in people of age As early as ten

Men Generally black of dark hair Women Red and blond hair

En.wikipedia.org/wiki/Human_hair_color Google images