They can be, in the full biological sense, quite distantly related, while still having an exact match in their mitochondrial sequences because their maternal lines trace back to the same ancient ancestral woman.

Mitochondrial DNA accumulates mutations at a roughly predictable rate.

Over time, specific mutations become characteristic of specific matrilineal lineages, and these lineages are classified into haplogroups — clusters of related sequences that share common mutations.

The haplogroups of Native American mitochondrial DNA have been extensively characterized, and the major haplogroups associated with Indigenous American populations (typically designated A, B, C, D, and X, with various subgroups) all reflect the ancestry of the founding population of the Americas from northeastern Asia.

For the Kwäday Dän Ts’ìnchi project, the mitochondrial DNA recovered from the ancient remains was sequenced and characterized.