The paper reported results from the testing of Anderson’s mitochondrial DNA, comparing it against two reference samples: the mtDNA profile derived from the 1991 Romanov grave remains (compared against Prince Philip’s reference profile) and the mtDNA profile of Karl Maucher, the living Schanzkowska maternal-line relative.
The exclusion from the Romanov line was based on six positional differences in the hypervariable control region of the mtDNA. This is a robust exclusion: six differences in the region examined is a substantial divergence that cannot be attributed to sequencing error or minor measurement variation.
The match to Maucher was an exact match. Identical mtDNA sequences in the hypervariable region are consistent with a shared maternal ancestor. The probability that this match was coincidental was estimated at approximately 1 in 300.
The paper’s conclusion was carefully worded to reflect what the evidence established: that Anderson’s mtDNA was inconsistent with a maternal relationship with Tsarina Alexandra (excluding her as Anastasia), and that it was consistent with a maternal relationship with Karl Maucher (supporting the Schanzkowska identification). The phrasing acknowledged the distinction between an exclusion — which is what the Romanov comparison produced — and a positive identification, which requires a higher evidentiary bar and depends on contextual factors beyond the DNA alone.
The supplementary testing of nuclear DNA via STR analysis, which showed four of five markers inconsistent with a parent-child relationship with Nicholas II and Alexandra, provided independent corroboration of the mtDNA exclusion through a different analytical method.
Two independent laboratories. Two types of DNA analysis. Two separate biological samples. All reaching the same conclusion.