stem cells
Genotoxic stress, namely anything that damages the genetic code of life DNA, causes a malfunction of the cells ultimately responsible for hair colour.
The stress sets off a chain of reactions involving specialised cells called melanocyte stem cells, their work on mice in Cell journal reveals.
Similar mechanisms appear to be at work in humans too, they say.
The findings could help explain why people with Ataxia telangiectasia, a rare, neurodegenerative syndrome caused by a mutation in a gene called ATM, go grey prematurely.
In their study, Dr Emi Nishimura and colleagues found the ATM "caretaker" gene serves as a checks and measures system to stop melanocyte stem cells going awry.
It is the job of these cells within the hair follicles to make the mature pigment-producing melanocytes that give hair its youthful colour.
doug
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