Around 300 AD in Levanluhta area in Isokyro, SW Finland, something extraordinary was initiated. They buried the deceased in a lake; this habit was continued for at least 400 years. When trenches were dug in the local fields in mid-1800's skulls, and other human bones were surfacing. In the anoxic, ferrous water, these bones had been preserved almost intact. For over 150 years now, archaeologists, historian, and locals have been wondering about these findings.
A multidisciplinary research team at the University of Helsinki decided to re-investigate the mystery of Levanluhta in 2010. Believed to be a sacrificial spring, the site is exceptional even in global scale and has yielded c - 75 kg human bone material altogether.
The leader of the research group, Docent Anna Wessman, had an ambitious aim: to discover who the deceased buried in Levanluhta were, and why they were exceptionally buried under water so far from dwelling sites. After several years of scientific work, the team reported its results in the most recent issue of Nature. The results are part of a more extensive international study shedding light on the colonization and population history of Siberia with DNA data from ancient, up to 31,000 years old, human bones.
Anna Wessman, the team leader, said that in their part, they wanted especially to find out the origins of the Iron Age remains found from Levanluhta.
The researchers used cutting edge ancient DNA sequencing technology in their investigation, which Department of Forensic Medicine is interested in due to the forensic casework performed at the department. According to Professor Antti Sajantila, the early phases of this project were demanding.
While talking about the first experiments in the laboratory, Sajantila explained that it was utterly frustrating when they were unable to repeat even their results.
Rapidly, the techniques were developing during the international cooperation, and ultimately, the first Finnish results were shown to be accurate. It was surprising, however, that the genomes of three Levanluhta individuals resembled those of the modern Sami people.
According to carbon datings of the bones belonged to people that died 500 to 700 AD, the results of the study suggested that the Isokyro region was inhabited by Sami people in ancient times. This analysis would be concrete proof of Sami in southern Finland in the past. However, the question is - were the people locals, recent immigrants, or haphazard by-passers? For the team to find out, other methods than DNA were needed. The solution lied in the enamel of teeth.
Curator Laura Arppe from the Finnish Museum of National History tells that strontium isotopes found in the enamel strongly suggest that the people grew up in the Levanluhta region.
