I could probably write a book on this one. "DNA 'evidence' relies on statistical analysis much more than on observed facts." And everyone should know that "there are lies, damn lies, and statistics"(OK mods, I know the language isn't according to Hoyle, but give me some slack, it's a famous quote attempting to put statistics in the lowest category of arguments).
So here's the concise version of the situation with human genetics. In attempting to draw conclusions from genetic comparisons it is necessary first to posit a reasonable assumption about what is actually known about past populations, their locations and historical movements. The Asian land bridge hypothesis usally is drawn to fit the receding ice sheetlocations, known from geologic and ice core drilling and soil tests, about 10000 years ago, when it is possible that a narrow land passage existed between the oceans and the ice that allowed hunting nomads to push along the thousand-miles gap to find larger ice-free areas and game to hunt on the American side of the passage. But nobody can actually know which direction those nomads moved, from Asia to America or from America to Asia. There is accumulating evidence that people were here before that ice-free passage opened up, by 20,000 years. There is also compelling evidence that sea peoples were sailing the Pacific coasts from Asia clear to America- or perhaps in the opposite direction--- 15000 years ago. Fact is, there are coastal island human cultural remains dating to that period which indicate a fishing economy and seafaring lifestyle.
Further evidence of European migrations around 25000 years ago link Eastern coastal site with sites in France.
The attempt to repudiate the Book of Mormon story with at least equally ignorant "science" is just useless and pointless. Internally, from the Book of Mormon, there are several migrations mentions, at least three from Eurasia to America and at least one back across the Pacific, or into the Pacific Islands at least. One of my ancestors was perhaps the first ordained LDS missionary to the Pacific, set apart to preach while working his livelihood as a sailor for the British merchant fleet. He recorded in his journals a vivid dream, some might call it a "revelation" but it was never claimed as a revelation by the LDS Church. In his dream he was informed that the Japanese were a Nephite branch. I myself went to the Philippines as a missionary, and my experience more or less satisfied my that they were a Book of Mormon "Lamanite" remnant.
One linguist studying the Polynesian languages and Egyptian history found cognate words between Polynesian and the northern Egyptian tribes of about 300 BC. Greek words being used in Polynesia. It is historically known that the Egyptians ran a huge ocean-going ships across the Indian Ocean and mined gold in Indonesia. The whole Malayo-Polynesian set of languages stretches from Madagascar to Formosa and steles in that alphabet have been found on the American Pacific Coast.
Oh this is already too long and I haven't even discussed the statistical calculations of how human gene pools change over time. Let it be enough to just say that the ignoramuses who have tried to claim science in drawing conclusions about the Book of Mormon peoples will before another hundred years goes by be looked back on as the true idiots they are. Too many over-the-top assumptions, and gross factual errors, to prove anything.