Male-line family tree
Y-chromosome DNA is passed from father to son through successive generations. Richard III had no known male descendants so in so order to trace his Y-chromosome one has, first, to go up through his family tree, to his great-great grandfather Edward III, before starting to move down to the present day. Edward III’s son, John of Gaunt, had an illegitimate son, John Beaufort, who was later legitimised and created Earl of Somerset, and it is from him that the Dukes of Beaufort are descended. Five present-day distant male relatives, all descending from Henry, 5th Duke of Beaufort, were traced, contacted and asked to provide DNA samples. From these it was possible to determine the Y-chromosome type of the 5th Duke, their common ancestor – the 3rd cousin, 11 times removed of Richard III.