HISTORIAN Julian Richards will be in the county town tomorrow for a study of the genetic clues to deadly diseases.

The scheme involves taking a small sample of blood from local people whose grandparents were born in the same locality.

The genetic make-up will be studied to look for links to diseases such as cancer and heart disease.

Tammy Day, who is one of the organisers of the People of the British Isles genetic map project, said they chose the Dorchester area as one of the collection points because of the stability of a rural population.

She said many people are likely to have all four grandparents born within the locality, making them ideal subjects for the survey.

She added: "People might have moved to Dorch-ester and left their roots in other parts of the UK and we can take those samples and refer them to the relevant area such as Scotland or Wales.

"We need people who have three or four of their grandparents born in one area in a radius of 30 to 40 miles such as the same parish, locality or county."

The team will be at St Peter's Church in Dorchester tomorrow and Wednesday.

Mr Richards, who has appeared in the BBC's Meet The Ancestors programme, will be at a reception tomorrow night in the church hall to introduce Professor Sir Walter Bodmer, who is leading the project, and who will give a talk.

Mrs Day said she hoped people would support the project by giving a blood sample on the two days.

A research team from the Department of Clinical Pharmacology of Oxford University is running the project on behalf of the Wellcome Trust.

They aim to collect 3,500 samples from all over the UK during the five-year study.

An earlier stage formed part of a Channel 4 television programme and revealed the high rate of Viking origins in Scottish islands.

The current phase will not inform people of their origins but will use their DNA to explore the effects of history and geography on the causes of diseases.