Native American DNA, Blood Quantum, and Tribal Membership

Blood Quantum, the Dawes Act, and Tribal Membership

Social and cultural definitions of relatedness are more consistent with traditional notions of tribal membership; however, the U.S. government has long imposed its own needs on tribal traditions. The Dawes Act of 1887 effectively dispossessed Native Americans of communal land holdings by conferring land allotments to Native American male heads of households. Persons believed to be full-blood Native Americans were given an allotment, but it was held in trust for 25 years, with the hope that Native Americans would eventually assimilate into the capitalist economic system. By contrast, persons deemed to be half-blood or less were immediately given their land allotment under the assumption that they were culturally advanced enough to successfully manage their holdings. This "blood quantum" strategy for managing tribal lands has remained in place since the Dawes Act became law, though this paternalistic approach moderated somewhat during the 20th century.

Enforcement of the Dawes Act imposed European-American notions of tribal membership on Native Americans — an approach that is entirely consistent with a population genetics framework for determining tribal membership. The Cherokee decision to disenroll the Cherokee Freedmen because of their African ancestry is a case in point, and it flies in the face of a traditional social and cultural determination of tribal affiliation. Tribal governments are worried about loosely affiliated people seeking tribal membership for economic reasons, which has encouraged increased reliance on genetics as a screening tool. Despite these pressures, some Native Americans continue to advocate for a return to a social and cultural basis for determining tribal affiliation. The most likely outcome, according to TallBear, is that blood lineages and genetics will always play a role in determining tribal membership, but that this will be moderated by other considerations — such as knowledge of tribal history, culture, politics, ethics, and language.

Mitochondrial and Y-Chromosome Haplogroups in Native American Ancestry

Tracing a person's ancestral lineage in modern times typically depends on mitochondrial or Y-chromosome genotyping. Since mitochondria and the Y-chromosome are inherited from mothers and fathers, respectively, they are used to determine maternal and paternal ancestry. Five mitochondrial haplogroups have been associated with Native Americans: A, B, C, D, and X. However, the X haplogroup can also be found in Europe and the southeastern region of Siberia. This has led to the formulation of a hypothesis that the ancestors of some Native Americans migrated from Europe to Siberia and then into North America. This remains a theory — and a controversial one. The strength of this evidence is also undermined by the fact that the five haplogroups are based on a relatively small sample of the Native American population and could therefore be misleading.

The Y-chromosome haplogroups C and Q have also been found in residents of southwestern Siberia, providing additional support for the hypothesis that the ancestors of Native Americans migrated from eastern Russia. TallBear, however, cites recent research revealing that 96% of Native Americans are predicted to carry one of three Y-chromosome haplogroups: C, Q, and R. The R haplogroup likely reflects admixture with Europeans. In addition, a significant percentage of Y-chromosomes from a relatively small sample (N = 588) of Native American males contained haplogroups from "other, more recent ancestry" (p. 43). As TallBear notes, a single person could have as many as 1,000 ancestors over the past ten generations, and even if they had two Native American grandparents there is a chance they would be excluded from tribal membership because genetic testing revealed no Native American markers. For example, a person could test positive only for the mitochondrial and Y-chromosome X and R haplogroups, leaving no way to determine whether they have Native American ancestors based on that evidence alone.