A cure for baldness has come a step closer with the discovery of the vital skin cells that are responsible for producing a good head of hair.
Scientists have also identified the genes that are active in the stem cells of the hair follicles that are responsible for generating body hair.
In experiments on mice, the researchers were able to transplant the stem cells of one animal's hair follicles to enable the hair to grow on the bald patches of another mouse.
George Cotsarelis, assistant professor of dermatology at Pennsylvania School of Medicine in Philadelphia, said that the study could lead to new ways of treating hair loss in humans through drugs or surgery.
"This may lead to a new type of tissue engineering for treating baldness - for example, isolating hair follicle stem cells from the scalp and reconstituting hair follicles in bald areas," Dr Cotsarelis said. "I can't predict the future but this type of research certainly opens new avenues for developing new treatments for baldness."
The study, published in the journal Nature Biotechnology, isolated the stem cells within the bulbous follicle at the base of a hair shaft. Sometimes these follicles go into a permanent resting phase, halting hair regeneration. When the researchers transplanted the stem cells into the skin of other mice, hair follicles began to re-grow within four weeks.
"Now that we can isolate stem cells involved in hair growth, we can develop targets for manipulating hair growth," Dr Cotsarelis said.
The research could also lead to treatments for burns victims where skin re-growth is needed.