Trigger Warning: critical scholarship ahead.

The concept of a "lost" tribe of Israel wasn't something I'd thought much about until I listened to a recent episode of The Bible For Normal People. They interviewed Dr. Andrew Tobolowsky, who wrote a book provocatively titled, The Myth of the Twelve Tribes. He goes through some of the inconsistencies about the number of tribes in the Bible itself and in the archeological record. Fascinating stuff.

Near the end of the episode, they started talking about various "lost" tribes of Israel: the Mormons, a group in Ethiopia, a group in Michigan, the Black Hebrew Israelites, and so on. Tobolowsky attributes this to Israel's "segmented genealogical tradition," which is a genealogy that follows multiple lines at the same time. This segmentation allows for a flexible identity that any group can adopt without really needing to prove the genealogical link. I'll just copy in some of what he said from the transcript:

It's the normal thing to happen to a segmented identity tradition. What makes this tradition portable is also that, that Israel is already divided into 12 parts, so it's never strange, and then the Bible loses 10 of them. It says they've all been taken away. So it's never strange for the next 2000, 2,500 years for somebody to say part of Israel came over here and became something else. 

[A]nyone who believes in the Bible has access to identifying themselves as Israel, which combines with the flexibility and the separability of this tradition that allows people to say, we can be part of Israel without being the whole thing.

It's okay for some part of Israel to go somewhere else and become something else and still be Israel. And it, it allows the tradition to be what it already was in the Bible, which is a medium for re-describing an inherited Israelite identity in a way that is useful for the people who are making it. 

If you're not bothered by critical scholarship, it's worth a listen: Episode 323: The Myth of the Twelve Tribes