PARIS, FRANCE - GENE detectives on Sunday said they had netted two genetic variants that, together, boost the risk of male baldness sevenfold.

The two variants are located on a stretch of DNA on Chromosome 20, according to a study carried out on 1,125 men of European descent.

'These variants are present in one in seven Caucasian men and provide novel insights into the cause of this common and sometimes distressing condition,' the team said.

Previous research has determined that male pattern baldness - also known as androgenic alopecia - has a highly genetic origin. Heritability accounts for 80 per cent of cases.

The study, published online by the journal Nature Genetics of the British-based Nature Publishing Group, was carried out by a multinational team from Britain, Iceland, Switzerland and the Netherlands.

One of the lead researchers, Dr Tim Spector of King's College London, said the findings raised questions as to the evolutionary origins of baldness and opened up new paths for cures for hair loss.

'The strong genetic basis of hair loss is odd, as any evolutionary advantage is unclear,' said Dr Spector in a press release.

'Clearly, most men know if they are bald or not. But early prediction before hair loss starts may lead to some interesting therapies that are more effective than treating late-stage hair loss.' (...) Given the feasibility of gene therapy in human follicles, our results may point to an intriguing new potential target for the treatment of hair loss in men and possibly women.'

By coincidence, a separate study also published in the same journal, reported that scientists had isolated a group of stem cells in mice that can repopulate and maintain all cell types of the hair follicle.

Androgenic alopecia can have a big social impact as it affects a man's self-image. Baldness is also associated with an array of health problems, including coronary heart disease and hypertension in men and polycystic ovarian syndrome and insulin resistance in women.

The reasons are unclear, but one theory is that some of the genes involved in hair loss also play a role in the molecular mechanisms for these diseases.

The newly-identified variants on the p11 stretch of Chromosome 20 add to telltale genes, located in the X chromosome, that are receptors for the hormone androgen. -- AFP