For DECADES, LDS scholars have been pointing out that the actual text of the Book of Mormon demands that it took place in an area no more than a few hundred miles across, with a “narrow neck of land” in the middle. It has a very consistent internal geography. If that is so, then there were probably all kinds of other people on the two continents. They also pick out some clues in the text there may have been some natives around who mixed in with the Book of Mormon peoples. This possibility had been discussed since the 1800’s in official Church periodicals.
If this is correct, then the kind of DNA evidence Southerton and others collect doesn’t amount to much. Lehi could still be AN ancestor of all living native americans very easily, but there wouldn’t be a recognizable DNA stamp.
That’s why Southerton and the others spend so much effort trying to prove that the early LDS, especially Joseph Smith, thought the Book of Mormon narrative covered most of North and South America. They know that their evidence doesn’t mean anything without this context. Well, if the book itself clearly indicates a much smaller area, but Joseph Smith didn’t realize this, then I conclude that Joseph Smith wasn’t the one who wrote the book. And I’m inclined to put more stock in what the book says about itself, given its claimed origin.
So after poring over all the DNA claims, I think the whole thing has actually been good for us. It’s forcing Mormons to dump their vague ideas about how it relates to history, and try to find more concrete links.
Related to that, you guys should listen to the Library of Congress talk given by John Clark, who is a very prominent Mesoamerican archaeologist. Yes, he is LDS, and works at BYU. And therefore, some people will automatically discount everything he says. However, this is a guy who is well recognized in the field, and he thinks that a very plausible case can be made for a Book of Mormon setting in Mesoamerica–Southern Mexico/Guatemala area.
Here is the link. Go to session 2 and skip ahead to Clark’s talk. Margaret Barker’s talk (she is a Methodist biblical scholar) is very good, too.