Our surnames and genetic information are often strongly connected, according to a study funded by the Wellcome Trust. The research, published this week in the journal Molecular Biology and Evolution, may help genealogists create more accurate family trees even when records are missing. It also suggests that the often quoted "one in ten" figure for children born through infidelity is unlikely to be true.

Dr Turi King and Professor Mark Jobling from the University of Leicester examined the Y chromosomes of over 1,600 unrelated men with forty surnames (including variations in spelling). Sons inherit both the Y chromosome and - generally - the surname from their fathers, unlike daughters, who do not carry this sex-specific chromosome and usually change their surname through marriage.

Hereditary surnames were introduced to Britain by the Normans at the time of the conquest. The practice of using hereditary surnames filtered down from Norman noble families to all classes of society so that by the fourteenth century people in many classes had surnames and by the sixteenth century it was rare not to have one.

Dr King and Professor Jobling found that men with rare surnames - such as Grewcock, Wadsworth, Ketley and Ravenscroft - tended to share Y chromosomes that were very similar, suggesting a common ancestor within the past 700 years…