CAMBRIDGE, MASSACHUSETTS—Past interpretations of the genetic closeness between Tutankhamun and his father Akhenaten suggested that Tut’s mother had to have been an unknown aunt. But French Egyptologist Marc Gabolde thinks that the genetic similarity between father and son could reflect three successive generations of marriage between first cousins. If so, then Tutankhamun’s mother may have been Nefertiti, known to have been Akhenaten’s wife and his first cousin.