The comparison group addresses this by providing a reference for what the “background” level of genetic sharing looks like between the historical sample and unrelated members of the same population. If the sharing between the historical sample and Ernie LaPointe is substantially greater than the sharing between the historical sample and other Lakota individuals, that excess sharing is the signal that indicates specific, traceable relationship.
The comparison group also serves as a kind of quality control. If the historical sample were too degraded to yield interpretable results, you would not expect to see any consistent pattern of differential sharing — the noise would swamp any signal. The fact that the researchers could identify a pattern of excess sharing for LaPointe specifically, against a background of Lakota-population sharing, is itself evidence that the sample yielded interpretable data.
The specific composition of the comparison group — how many individuals, from which communities, with what genealogical depth — would be detailed in the full paper’s methods. That level of specificity was not available in publicly accessible reporting on the study. What is available is the general principle and the researchers’ conclusion that the pattern they observed was consistent with a great-grandparent relationship.
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## The Question of Consent in Historical DNA Research
The Sitting Bull DNA study raises a question that has become increasingly important as ancient DNA research has expanded: what does meaningful consent look like when the person whose genetic material is being analyzed died more than a century ago?
Sitting Bull himself obviously cannot consent to the analysis of his DNA. The question of whose consent is required in his absence is answered differently by different legal and ethical frameworks.