The technical achievement required to produce this result — extracting and sequencing DNA from bones that had been frozen for five thousand years, using the sequencing technology available in the early 2010s — was not trivial, and the researchers who produced it were working at the frontier of what was possible.

The paper established several things that the 2023 reanalysis confirmed: Ötzi’s close genetic relationship to modern Sardinians, his Y-chromosome haplogroup (G2a4, characteristic of Neolithic Anatolian farmers), his blood type (O), and several genetic variants associated with specific health conditions including the cardiovascular risk factors that were subsequently confirmed by medical imaging.

What the 2012 paper got wrong was the apparent steppe ancestry — the genetic signal that the paper interpreted as indicating relationship to populations from the Pontic steppe.

This signal, it turned out, was introduced by contamination with modern human DNA that carried steppe ancestry.