OK, so Sophie and her unnamed brother are "direct descendants of Mary Magdalene and Jesus Christ."
Their dead parents "Incredibly, both had been from Merovingian families-direct descendants of Mary Magdalene and Jesus Christ"
So of their grandparents, which was the 'direct descendent' - Jacques Sauniere or Marie Chauvel?
Which of them carried the bloodline? Seems like it was Jacques, who was the Master of the Priory, with its onereous task of having sex on the altar, rather than Marie who doesn't know where the grail is and was only "married to a person of enormous influence"