Pictures: DNA Reveals Distant Origins of Ancient 'Gladiators'

Unusually, many of the bodies in the Driffield Terrace cemetery were beheaded. Some archaeologists think that suggests they were gladiators; others say they might have been criminals.

Trinity College Dublin geneticist Dan Bradley says the inner ear, or petrous, bone is a particularly good source of well-preserved DNA.

The skeletons found in the cemetery were all men under the age of 45.

The neck vertebrae of Roman-age skeletons found at Driffield Terrace by York Archaeological Trust show signs of decapitation.

The Driffield Terrace cemetery first came to light during renovations to the backyard of a local house.

The beheaded skeletons were buried with their skulls, which inadvertently helped archaeologists understand where they came from.