File photo: Xinhua

Danish scientists have managed to extract a complete human DNA sample from a piece of birch pitch of more than 5,000 years old, used as a kind of chewing gum, a study revealed Tuesday.

The sample yielded enough information to determine the source's sex, what she had last eaten and the germs in her mouth. It also told them she probably had dark hair, dark skin and blue eyes.

They found the sample during an archaeological dig at Syltholm, in southern Denmark, said Tehis Jensen, one of the other authors.

But they were not sure why their subject chose to chew the bark: whether to turn it into a kind of glue, to clean her teeth, to stave off hunger - or simply as chewing gum.

AFP