On your head right now! Dandruff's genes sequenced

By Maggie Fox, Health and Science Editor

WASHINGTON (Reuters) - First, researchers grew enough fungus to give dandruff to 10 million people.

Next, they sequenced its genes.

Then they found out that not only does an icky fungus live on your head and cause dandruff-- but it could be having sex. On your head. Right now.

A team at Procter & Gamble Beauty said on Tuesday they had sequenced the genome of Malassezia globosa, a fungus that grows on the skin of between 50 percent and 90 percent of the population. It causes dandruff and a range of other skin conditions.

Writing in the Proceedings of the National Academy of Sciences, the researchers said their study can shed light on ways to fight not only dandruff, but an infection that can threaten the lives of newborns.

"A complete genomic sequencing of a Malassezia genome opens tremendous opportunities for researchers to understand the interactions of fungi and humans," said Thomas Dawson, a scientist at P&G Beauty who led the study.

"It's amazing that the understanding of the genetic make-up of a microscopic organism can have broad implications ranging from human health to agricultural science."

The team at P&G Beauty, a subsidiary of the company that makes household products ranging from toilet tissue to shampoo, said M. globosa is capable of excreting more than 50 different enzymes that help digest and break down compounds in the hair and scalp.

"The M. globosa genome sequence also revealed the presence of mating-type genes, providing an indication that Malassezia may be capable of sex," they wrote in their report.

Other fungi can reproduce sexually, but this particular type had not been known to, Dawson's team said. This means it could find a way to evade dandruff shampoo.

They said dandruff can affect up to 90 percent of people, and that it has been known for more than 100 years that Malassezia can cause dandruff and eczema.

Malassezia fungi also cause systemic infections in newborns, and is related to some fungi that affect plants such as corn.

The fungus joins organisms ranging from yeast to rice to human beings that have had their genomes sequenced.

Dawson's team said they grew 10 liters of the fungus, "equal to the amount of fungus that would be found on the heads of 10 million people," the company said.

(Reporting by Maggie Fox; Editing by Julie Steenhuysen)