The link is via the Y chromosome--the part of our genetic material that confers maleness and is passed, like many surnames, from father to son. A simple correspondence between name and Y chromosome could in principle connect all men sharing a surname into one large family tree. However, in reality the link may be weak for a number of reasons--for example, the existence of multiple independent founders for many names, adoptions, name changes, and non-paternities. Nonetheless, previous research had suggested a genetic link for some particular names.
The new study, from Turi King, Stéphane Ballereau, and Mark Jobling from the University of Leicester and Kevin Schürer from the University of Essex, examines the issue more generally by analyzing many names and recruiting pairs randomly from the population. Pairs sharing surnames are on average much more likely to share Y chromosomes than pairs with different names, and the link becomes stronger as names become rarer. For example, there is no link for Smith, Jones, and Taylor, but a clear link for Attenborough, Widdowson, and Grewcock. Linked men share a common ancestor from less than 20 generations ago (about 1300 AD), when surnames were founded. The research has important implications for genealogists wishing to connect branches of their family trees, and also in forensic science, since it suggests that, given large databases of names and Y chromosome profiles, surname prediction from DNA alone may be feasible.
The researchers include Turi E. King, Stephane J. Ballereau, and Mark A. Jobling of the University of Leicester in Leicester, United Kingdom; Kevin E. Schurer of the University of Essex in Colchester, United Kingdom. T.E.K. was supported by a Wellcome Prize Studentship (grant no. 061129), S.J.B. by the Wellcome Trust, and M.A.J. by a Wellcome Trust Senior Fellowship in Basic Biomedical Science (grant no. 057559).
King et al.: "Genetic Signatures of Coancestry within Surnames." Publishing in Current Biology 16, 384–388, February 21, 2006. DOI 10.1016/j.cub.2005.12.048 www.current-biology.com