Which 12 tribes? Do you use the list in Revelation 7? Or another list? The Bible lists the twelve tribes of Israel in several locations: (Genesis 35:23-26; Exodus 1:2-5; Numbers 1:20-43; 1 Chronicles 2:2; Revelation 7:5-8). It is interesting that there are slight differences in some places. The 12 sons of Israel (Jacob) were Reuben, Simeon, Levi, Judah, Issachar, Zebulun, Benjamin, Dan, Naphtali, Gad, Asher and Joseph. These were the ancestors of the original twelve tribes. However, Reuben lost his rights as firstborn by defiling Jacob’s bed (Genesis 35:22; 49:3-4). In Reuben’s and Joseph's place, Joseph’s two sons, Ephraim and Manasseh, became tribes of Israel (Genesis 48:5-6). As a result, the twelve tribes became Simeon, Levi, Judah, Issachar, Zebulun, Benjamin, Dan, Naphtali, Gad, Asher, Ephraim and Manasseh. In some other lists of the twelve tribes of Israel, Levi is not mentioned, presumably because the Levites were assigned to serve at the temple and therefore were not apportioned land of their own in Israel (Joshua 14:3.
All this to say your premise that DNA is what defines God chosen people is ridiculous. How did Rahab become included in that line? Or how about King David, he came from a Moabite woman, or have you not read the book of Ruth?
"Be a listener only, keep within yourself, and endeavor to establish with yourself the habit of silence, especially on politics." -Thomas Jefferson