This is because after 2 or 3 thousand years, perhaps even less, DNA begins to degrade. Moreso if the tissue that it’s part of is dehydrated by elements other than desert sand & heat & preservatives like myrrh,aloes, & frankincense. The royal personage is reasonably well – preserved, but those elements have more than likely shortened the DNA ” chain ( s ) ” containing vital information on who these royals were in life. & why cloning Rameses or “King Tut ” is highly unlikely. As to incest among royals & nobles in Egypt, this practice was part of their belief system : The nobles were supposedly descended from the gods, so marriage outside the noble / royal lineage, in effect, ” diluted ” their divinity. King Tutankhamun was married to his sister, Ankhesenamun, even though the union didn’t produce an heir to the 18th dynasty throne ( & 2 small mummified fetuses were discovered in ” King Tut’s ” tomb ) whereas Rameses the Great produced a small legion of royal heirs.
Egypt is a big area of interest of mine, & not just because of mummy movies. 🙂 I’ve seen ” Treasures of Tutankhamun ” on one of the exhibition’s visits to the U.S. ( 1977 ) & a Rameses the Great exhibit in Memphis in 1987. & my stepsister has been to the Valley of the Kings albeit roughly 2 decades ago.
King Tut is the only 18th Dynasty pharaoh whose mummy has been identified with certainty, says a new analysis.