Further genealogical research to identify a common ancestor for all seven X-surnamed males suggests that the hgA1 Y chromosome must have entered their lineage over 250 years ago. However, it is unclear whether the male ancestor was a first generation African immigrant or a European man carrying an African Y chromosome introduced into Britain some time earlier, or even whether the hgA1 Y chromosome goes back as far as the Roman occupation.
"This study shows that what it means to be British is complicated and always has been," says Professor Jobling. "Human migration history is clearly very complex, particularly for an island nation such as ours, and this study further debunks the idea that there are simple and distinct populations or 'races'."
In addition, Professor Jobling believes that the research may have implications for DNA profiling in criminal investigations.
"Forensic scientists use DNA analysis to predict a person's ethnic origins, for example from hair or blood samples found at a crime scene. Whilst they are very likely to predict the correct ethnicity by using wider analysis of DNA other than the Y chromosome, finding this remarkable African chromosome would certainly have them scratching their heads for a while."