Your surname may well be written in your genes, a study has shown.
This surprising discovery suggests that forensic evidence left at the scene of a crime could be read in a DNA laboratory and reveal the criminal's name.
Professor Bryan Sykes and Catherine Irven of the Institute of Molecular Medicine at University of Oxford started the research as "a bit of fun", but it is likely to have an impact in both forensic science and genealogy.
Professor Sykes used samples from 61 volunteers who shared his surname to establish a link between the name and the distinctive DNA. He has found similar results for three other names, but thinks the link may not hold for the most common surnames like Jones and Smith.
Fathering a dynasty
The research makes the first direct link between genes and genealogy, showing that successive generations of a family can inherit unique sections of DNA.
This strongly implies that people sharing a surname share a single male ancestor. Genealogists had long assumed that there would be several founders for every family name.
"It puts every family on a par with the aristocracy, in being able to trace ourselves back to an original founder," said Professor Sykes.
The name Sykes means a boundary stream and is a common landscape feature in Yorkshire, suggesting a number of people could have adopted it in the 13th and 14th centuries, when inherited surnames became common.
History of infidelity
It has been traditional in England for children to take their father's name and so Professor Sykes and colleague Catherine Irven looked at the Y chromosome, which fathers pass to sons but not daughters.
They randomly chose 250 men with the name Sykes and asked for DNA samples: 61 replied with a swab from the inside of their cheek.
Half of the group shared four unique sections of DNA which were not found in control subjects either in Yorkshire or other areas of the UK.
The other half did not have the Sykes DNA, suggesting some infidelity in the Sykes dynasty. However, the estimated rate of infidelity over the 700 years the name has existed for is very low.
If just 1.3% of the Sykes children in each generation were fathered by someone other than a Sykes, then the accumulation of "foreign" genes would mean that about half of today's Sykes would not have the unique DNA.
This uncertainty means the DNA evidence of a name could not be used to convict criminals, but it could help to narrow down searches. It is also likely that families with the most common names, like Smith and Jones, do have multiple founders.
The research is published in the American Journal of Human Genetics.