Some questions that many have about the Book of Mormon and archaeology or genetics are questions, in part, created by oversimplified and fundamentalist assumptions about the Prophet Joseph Smith and scripture. Some of these assumptions were pronounced by the earliest Mormons and passed on as folklore.
One of these fundamentalist assumptions is that the Book of Mormon is a history of the Indians, that Indians are simply "dark skinned Jews". Forget that the books in the Book of Mormon are royal lineage histories. In each lineage history, the record focuses on the elites of one royal house, with little attention given to the rank and file. Forget that the book's own internal geography describes an area the size of Pennsylvania, not North and South America. It never was a history of the Indians, even if Mormons said it was.
Another fundamentalist assumption is that the Lehites and Jaredites represent distinct cultures and civilizations, apart, alone in ancient America. This assumption posits that the Nephites are to native America what penguins are to Antarctica, distinct, with genetics, language and culture that resisted any kind of genetic or cultural assimilation. Forget that the Book of Mormon's own definition for Nephite and Lamanite resists such oversimplification(Jacob 1:14,4 Nephi 1:20,34-36). Forget that the biggest problem facing their Arabian born, spiritual leader, in the first generation, was unsanctioned polygamy and not just any polygamy but the polygamy of David and Solomon. David and Solomon were guilty of taking plural wives from other nations and by acquiring wives through murder(Jacob 2:24,1 Kings 11:1, 2 Samuel 12:9-13).
Where the first generation of Nephites conquerors and marauders over an indigenous population? The problems of Jacob's community are hardly the problems expected of an isolated, Hatfields vs McCoys, scenario. The fundamentalist assumption of a lily white and isolated, almost Ashkenazic, civilization ignores the fact that a small immigrant community of, at most 30 people, would be genetically, linguistically and culturally swallowed by the millions of indigenous people already here, whose distant ancestors came over the Behring Strait, thousands of years before.
Fundamentalist assumptions about the Book of Mormon have fed an ill informed desire to find Crown Heights in ancient america, as if the archaeology of the Egypt were comparable to the archaeology of Mexico. It isn't and we still can't find the city of Punt. We will not be able to pinpoint Zarahemla, until we know what Nephite era sites like Chiapa de Corzo were originally called and who lived there, we still don't. Archaeology is great when it comes to studying population growth, migration, agriculture and ceramics. It is very weak when it comes to identifying individuals and understanding their thoughts. For that, you need written texts, which are so very rare for ancient America.