The mtDNA of the so-called 'Princes in the Tower' (King Edward V and his brother, Richard of Shrewsbury, Duke of York) should be identical to that of their female-line niece, Mary Tudor, Queen of France and Duchess of Suffolk.
Several locks of Mary Tudor's hair were cut off when her tomb was opened in the 18th century. One lock of Mary's hair is preserved in Moyses Hall Museum, Bury St Edmunds. The museum authorities gave permission for a few strands of this hair to be tested for mtDNA, but sadly it proved impossible to open the Bury St Edmunds locket, which had been soldered to seal it.
Later, John located a second locket containing a very well preserved lock of Mary Tudor's hair. The owners kindly gave John some strands of the hair, and an attempt was made to determine the mtDNA sequence, but so far this has not proved successful.
John also researched the female-line descendants of Jacquette de St Pol, Duchess of Bedford and Countess Rivers (the maternal grandmother of the princes). All her female line descendants should have mtDNA identical to that of the 'Princes'. However, it has not been possible to find any all female-line living descendants of this family.