Are you Saxon, Viking, Norman or Celt?

An Oxford research team wants to help you find out: It is aiming to draw a genetic map charting the ancestry of people living in Britain, and is particularly interested in Oxfordshire, as the county may hold the key to discovering how invading hordes of Anglo-Saxons, Vikings and Normans moved across the country.

The researchers, based at the Radcliffe Infirmary, in Woodstock Road, have already taken 2,600 DNA samples from volunteers.

But they need just under a thousand more people to donate a tablespoon of blood in order to complete their project.

The group especially wants to hear from people who had four grandparents who grew up in Oxfordshire - in order to take the purest possible reading for the area.

Volunteers will have strands of their DNA analysed and compared with that of people living in other countries.

Certain genetic markers, such as a DNA strand found in people with red hair, will then help the researchers identify that person's ancestry - and help them plot how the conquering hordes lived and bred more than 1,000 years ago. A pilot project has already discovered that half of Oxfordshire's natives have an Anglo-Saxon origin, while the other 50 per cent are descended from Celts.

Dr Bruce Winney, a geneticist involved in the project, said: "Oxfordshire is one of the regions we're really interested in because there has been a lot of Anglo-Saxon impact here over the years.

"The split between Anglo-Saxons and Celts suggests that the Anglo-Saxons came in but they did not completely wipe out the ancient Britons.

"There are probably more Anglo-Saxons in the east of the country but the further west they came across, the more they were breeding with the Celts."

The project cannot yet determine whether the Anglo-Saxons in Oxfordshire have descended from Angles originating from central Denmark, Saxons from northern Germany or Jutes from northern Denmark.

Dr Winney added: "We haven't done much with the Vikings yet but the Vikings that had an influence here were the Danish Vikings - and they came from the same place as the Anglo-Saxons 200 years before."

To complicate matters, the same Danish Vikings established themselves in Normandy, in northern France, and then invaded England in 1066 - which Dr Winney said meant that from a genetic point of view England had effectively been invaded three times by the Anglo-Saxons.

At the moment, volunteers will remain anonymous and results will only determine the genetic make up of the area, rather than that of individuals.

But Dr Winney added: "In a few years time we will have the genetic markers available to us that will tell people just how much Anglo-Saxon or Celtic ancestry they have themselves."

Samples will be collected at the Uffington Show today and tomorrow.

Call 01865 863819 for more information.