Ten years ago, population geneticists could study only relatively simple genetic configurations from the Y chromosome and mitochondrial DNA. Since then, there has been a revolution in the methodology available for this kind of study so that now scientists are examining the most complex areas of an individual's complete nuclear DNA. Using what is called "admixture mapping," they look at thousands of variant SNPs (pronounced "snips" for single nucleotide polymorphisms) revealing the subtlest influences on an individual's genetic makeup.
Native Americans are so closely related, there appears to have been only one migration to the Americas from Siberia some 17,000 years ago.
What about the question of later migrations to the Americas? That issue has received less attention but is equally profound and is being illuminated by the same methodology. For instance, a study by Chao Tian and others, entitled "A Genomewide SNP Panel for Mexican American Admixture Mapping," in the June 2007 issue of the American Journal of Human Genetics, looked at 400,000 SNPs for "ancestry-informative markers." They wanted to determine ethnic origins for indigenous diseases, but their conclusions have implications for those interested in Book of Mormon studies.
From his office in Canberra, Australia, Dr. Simon Southerton recently commented on "the beauty of SNPs, which is that they don't just show us someone's dominant heritage." Southerton is a molecular geneticist who has written about genetics and the Book of Mormon. "They tell us what ancestors of other ethnic backgrounds are hiding unnoticed in our family trees."
Some Mormon literalists have conceded that since there were so few Israelites among millions of Siberians in the Americas, their genetic legacy is unobservable, while nevertheless remaining convinced that Israelites numbered among the ancestors of Native Americans.
"It's no longer possible to say that the genetic evidence is unavailable because it became extinct," Southerton explains. "If there were Lamanites in the Americas, they will be found. If there weren't, we'll learn that too. The recent technological advances have changed everything."
Southerton says that "anyone interested in the Mormon angle, hold onto you seats because you're in for a ride. The results are going to start pouring in."
It will take time for scientists to sort out which SNPs are indigenous to which regions, but a comprehensive database is emerging. Tien's study identified 8,144 SNPs found only among the Pimas and Mayas, distinguished for instance from European SNPs. They can be used to determine when "other DNA" entered the gene pool of American Indians. In all, out of 24 Mexican Americans in the study, the foreign DNA in their pedigrees "originated within the last 10-25 generations," Tien wrote. Southerton added that "if any of these individuals had pre-Columbian DNA from elsewhere in the world, it would have been virtually impossible to miss."
Two Mormon-oriented groups have found ways to explain away the pre-SNP absence of evidence for ancient Israelites in the Americas. The Foundation for Indigenous Research and Mormonism (FIRM), led by Rod Meldrum has argued that the mitochondrial X haplotype concentrated in New England tribes shows a pre-Columbian arrival of Israelites.
In response, Southerton says that "the consensus is that the mitochondrial X haplotype came to the Americas by way of Siberia, and there's not any real controversy over this among scientists. It most likely originated in Central Asia and left a trace as it spread to Europe, the Middle East, Asia, and then into the Americas about 15,000 years ago."
The Neal A. Maxwell Institute for Religious Scholarship at BYU, argues a Central American setting for the Book of Mormon and contends that a small group of thirty people would not leave a genetic trace among millions of Siberians in the Americas, so the absence of evidence is actually positive evidence for the Book of Mormon in that it is what one would expect.
"The genetic tests are now so sensitive," Southerton says, "that it is possible through admixture mapping to detect a tiny fraction of a percent of the mixed ancestry in a person's DNA. If a small family of Jews mixed with American Indians 3,000 years ago, the Jewish nuclear DNA would spread throughout the adjacent populations like a drop of ink in a bucket. It would be virtually impossible for it to go extinct. If it is there, we'll find it."
A 2010 study by Katarzyna Bryc and others, "Genome-wide Patterns of Population Structure and Admixture among Hispanic/Latino Populations," in Proceedings of the National Academy of Science in the USA, gives an admixture map for over 200 American Indians, showing European chromosome segments in red, African in green, and Native American in blue (figure 3, middle portion).
"If there were a lot of very short segments of foreign DNA on the admixture map," says Dr. Southerton, "it would suggest a pre-Columbian entry of that DNA. It would stand out like a sore thumb and be trumpeted around the scholarly world as an amazing discovery." There is also, according to the article, "a disproportionate contribution of European male and Native American female ancestry" evident in the map, as well as confirmation that European genes came primarily "from the Iberian peninsula." The goal of the study was to try to isolate genetic heritage associated with certain diseases.