I asked Perego about that, and he acknowledged the issue, but noted that the tests of Native American's aren't as conclusive as anti-Mormons want to claim. There was an interesting exchange I had with him.
Were you aware that scientists can’t distinguish between Viking DNA and Columbus DNA? Do you think it’s possible that the DNA from Lamanites simply can’t be distinguished?Ugo: Do you think we can determine DNA from 1800 versus DNA from 1000 A.D. from Europe found in America?
GT: I would think so.
Ugo: The answer is no. Do you know the Vikings were in Greenland from 1000-1400 A.D., 400 years? We have written documentation that they were here, the Icelandic woman actually kept their record of their voyages. We have villages, remains of Viking villages in Greenland that around 1400, they just left. They just left. We also have DNA from Native Americans in Iceland, which pre-dates Christopher Columbus, that’s been there. So we know probably these Vikings took some women to Iceland, and that’s why we have their DNA there. But where is the Viking DNA in America?
GT: That’s a great question. I have no idea.
Ugo: Well I’m sure it’s there, but there is not enough time for the post-Columbus DNA, to differentiate it from the pre-Columbus DNA. So whenever we find European, Middle Eastern, or African DNA in the Americas, even among tribes, native tribes, by default, scientists always say, we think this is post-Columbian admixture. But we don’t know, because the rate of mutation of DNA is not as fast as 100 years or 200 years.
Mitochondrial DNA, we actually measure one mutation every 5,000 years, mitochondrial DNA, which is one of the studies that have been done. So the point is we do find European DNA among Native tribes, but we always think that came with the Spaniards or with the Europeans. The first 200 years that they were here, they did whatever they wanted.
So you go to a reservation and you test a hundred people, you find 60 of them that might have Native American DNA, and then you find 40 that have European DNA. You think, well, this is the Spaniard mixing with them. They kept culturally their identity, but genetically we don’t know. We don’t know where that came. 2,600 years ago is not enough time to differentiate DNA from Europe, from post-Columbian to pre-Columbian DNA. It took 15,000 years for DNA to slightly differentiate it from the Asian counterpart.
Even today if you take a DNA test with Ancestry.com or with 23andMe or Family Tree DNA, they put Asian and Native American together in the same group, because they can’t make the differentiation. So if you find European DNA in a native group, you put it with Europe, but you think by default. In fact if you read any paper by any population scientist, they will not say, this is post-Columbian DNA. They say, most likely it is post-Columbian DNA, but we don’t know.