If you compare your genetic information with that of members from a reference population, you can estimate how long ago an ancestor belonged to that population based on statistical patterns of inheritance.
But your estimate is only as good as your reference.
Bustamante could not use U.S. tribal groups as a reference, because many have declined to participate in genomics studies and have refused to deposit DNA in publicly available databases. (More on that later.)
In the case of Warren’s individual DNA test, Bustamante resorted to what he considered the next best reference: 37 individuals from Mexico, Peru, and Colombia. According to Western scientists—who prefer migration theories that are culturally incongruent with indigenous origin stories—indigenous individuals from these countries represent the closest “sampled” biological relatives to Native Americans (that is, to those who originally inhabited what is now the United States).
This approach leaves a lot to be desired.
There is a great deal of diversity among the 573 federally recognized tribes in the contiguous U.S., all of which have unique cultural, linguistic, and historical traditions, as well as genetic differences. Of course, there exists even greater genetic heterogeneity among indigenous populations across the Americas. The terms Native American and indigenous are not interchangeable. While indigenous is ascribed globally, Native American is usually specific to the tribal peoples of the U.S.
Bustamante concluded that Warren had a “Native American” ancestor in her pedigree six to 10 generations ago, but he should have used the more general indigenous in his report.
In relation to the larger issue here, Native American U.S. tribes have the sovereign right to establish their own enrollment rules, and to my knowledge, they all consider DNA evidence to be insufficient. Indeed, the Cherokee Nation has already denounced the use of DNA tests to claim ancestry as “inappropriate and wrong.”
Who we are—the languages we speak, the traditions we practice, our broader cultures—inform our identities far more than DNA. Culture is not the same as a few genetic biomarkers, especially when those markers have statistical commonality to indigenous people with vastly different histories than Native Americans of the U.S.
Warren seems to get that. She stated, “I’m not enrolled in a tribe and only tribes determine tribal citizenship.” She is not seeking tribal enrollment and she does not (at least currently) claim to identify as culturally Native American.
Warren was born and raised in Oklahoma, which is also home to the descendants of those who were forcibly relocated from the southeastern states by President Andrew Jackson under the Indian Removal Act of 1830. She says she was told of her Native American heritage from childhood, and it’s understandable that she would want to check family lore against the seemingly hard evidence provided by a DNA test.