From what I have read the correct statement was that
"The American team, working blind, correctly identified the subject as North African."
The Thutmosids hail from Thebes, which technically is Upper Egypt, but is situated geographically somewhat in the middle of the map.
You should realize that the parent of Tutankhamen are not really known. It is speculated that his parents are Akhenaten and Kiya, but this is by no means certain.
On top of that Kiya is rather mysterious and some think she's a Mitanni Princess. (I'm agnostic on that one)
They are fairly certain that Tiye's mummy has been identified, and here you're just wrong. She is not black. Check out her mummy. There's a link to her mummy on this page:
http://members.tripod.com/anubis4_2000/Bookmarks.htm
Tiye's parents, named Yuya and Tuya, were buried in the King's Valley and again they are not black. Their remains can also be viewed on the above site.
I have to say that I find this whole racial nonsense really tiring and boring. Who cares? There were many great black people in ancient egypt. It just seems that occasionally there were some "north african types" too.
I get the impressions the ancient egyptians would have considered this a weird distinction to make. They just thought they were superior to everyone non-egyptian

I don't think they cared greatly about color.
They depicted themselves as reddish brown. Somewhere between the "asiatics" (as they called them) and the Nubians.
Modern Egyptians also find the debate rather strange.
As one said to me recently: Egyptians come in different colors and they get darker as you move south.
Does the skin color of an individual change the greatness of the civilization?