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## Anna Kjellström and the Path to DNA Testing
The sequence of events that led to the 2017 DNA study did not begin in a genomics laboratory. It began with a set of bones that had been sitting in museum storage for more than a century.
Anna Kjellström is an osteoarchaeologist — a specialist in the analysis of archaeological human remains — based at Stockholm University. Her work involves examining skeletal remains from archaeological contexts and interpreting what they can tell us about past populations: age at death, biological sex, health, diet, physical demands of labor, and more. She has worked extensively with Viking Age material from Birka and other sites.
When Kjellström examined the bones from grave Bj 581, she brought to the examination both modern osteological methods and the long previous history of the remains’ interpretation. The bones available for study were incomplete — roughly forty elements from what was once a complete skeleton, with the skull bones that carry the clearest sex markers absent or too fragmentary to use. What remained included forearm bones and pelvis fragments that, in Kjellström’s assessment, were more consistent with female morphology than male.
This was not a new conclusion — Berit Vilkans had reached essentially the same assessment in the mid-1970s. But Kjellström’s 2016 assessment came at a moment when the tools to test the interpretation with a different type of evidence had become available. Ancient DNA analysis had advanced to the point where it could extract genetic material from degraded archaeological bone and tooth, sequence it reliably enough to make meaningful statements about biological sex and ancestry, and verify that the material was genuinely ancient and not contaminated by modern DNA.