Here are some thoughts from
IRR.org:
In 600 BC there were probably several million American Indians living in the Americas. If a small group of Israelites, say less than thirty, entered such a massive native population, it would be very hard to detect their genes today. However, such a scenario does not square with what the Book of Mormon plainly states and with what the prophets have taught for 175 years.
Right, because the BoM says that the Lamanites were the principal ancestors of Native Americans. The whole mythology is built on this.
Here’s two reasons why the “what if the guys who came to America didn’t have the marker” argument is silly:
Code:
We know that Lehi and his associates in the Book of Mormon were Israelites, and we know a great deal about the DNA lineages of living people whose ancestors were Israelites reaching back 2600 years ago. Israelite DNA lineages belong to the same family groups found in European populations: the H, I, J, K, N, T, U, V, W and X groups. Essentially all Europeans and Israelites possess one of these lineages. In fact, other Middle Eastern populations such as the Syrians, Egyptians, Lebanese and other Arabic groups have similar mitochondrial DNA lineages belonging to these families. There is a smattering (<0.4%) of lineages in American Indian populations that are clearly, exclusively of European origin, most probably from Spain rather than from the Middle East. However, scientists justifiably assume that these lineages represent post-Columbus intermixing. The lineages in question are most common in North American tribes that had the greatest impact with Europeans and are very uncommon in Mesoamerica, which FARMS claims is the only "plausible" site for the Book of Mormon. In addition, European mitochondrial lineages are extremely rare in Polynesia.
If the number of Israelites traveling to the New World was as big as it would have had to be, then at least SOME of "the guys" would have had "the marker."
Finally, this little factoid is, to me, one of the more damning to the Mormon position:
The amount of DNA variation found in each of the five American Indian female DNA lineage families indicates that they have been present in the Americas for at least 15,000 years, possibly longer. This predates the existence of Israel by many thousands of years.