The
cause of white hair is not always genetics. However the two main reasons of
gray hair is because of age and genetics. Genes control the exhaustion of the
pigment potential of each hair follicle. Each different hair follicle has its
own different rates. In certain people, this rate occurs much quicker. 
Human hair grows in stages in which
a part of a hair is either growing or resting at a certain hair. Hair follicles
contain pigments called melanin. The hair becomes colorless when the body stops
producing pigments. This results in white hair, whereas gray hair is produced
from a result of pigment dilution.
The two pigments that give hair its
color are eumelanin and pheomelanin. Each human has a bit of pheomelanin in their
hair, which is hair color orange and yellow. It is found that two gene pairs
control human hair color. Several gene pairs control the light versus dark hair
in effect. The children born with some hair colors that darkens with growth,
which is caused by genes being turned off and on during early puberty. The two
genes responsible for gray hair is Bcl2 and Bcl-w.
Link 1: http://www.nytimes.com/2009/03/10/health/10well.html?_r=0
Related link: http://www.womansday.com/style-beauty/beauty-tips-products/why-does-hair-turn-gray-118871
This was interesting to read about. Since about the age of 25 my uncle has had pure white hair, which came on pretty rapidly. So I can imagine that his body stopped producing pigment at such a young age for some reason. Speaking of those who have hair color their whole lives, or most of it, I recently learned that red heads keep their pigment much longer than any other hair color, allowing them to keep from graying until much older.
ReplyDeleteI find this very interesting because I always thought that grey hairs comes with age and stress for everyone. Now that I think about it though genetically I guess some people have a higher chance at having grey hairs since people react to stress and age differently.
ReplyDeleteIf grey hair really is genetic, I hope I don't get my father's genes for that because he's been greying for years now. Maybe if I try to live a life without much stress (yeah right!) I won't get grey hair too early.
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