The study’s findings were specific, carefully stated, and significant within their scope.

They were not a solution to questions that were beyond their scope.

What Degraded DNA Can and Cannot Tell Us

The scientific method at the heart of the Sitting Bull study has implications that extend well beyond this specific case, and understanding those implications requires understanding more precisely what the technique does and what its limitations are.

The challenge of extracting useful genetic information from old biological material is a challenge of chemistry and statistics simultaneously.

Chemical degradation breaks DNA into fragments; the longer material has been preserved, and the more variable the preservation conditions, the shorter the surviving fragments tend to be.