NEW YORK (GenomeWeb) – A genetic analysis of DNA from more than a dozen ancient individuals buried in a 7th century cemetery in southern Germany suggests that warriors from an Alemannic confederation of tribes in the Upper Rhine region and beyond included individuals from northern Europe and from southern Europe or the Mediterranean.
"These results prove the existence of remarkable trans-regional contacts," first and co-corresponding author Niall O'Sullivan, a researcher affiliated with EURAC Research in Italy, the Max Planck Institute for the Science of Human History, and the University College Dublin, said in a statement. "The fact that they were buried together also indicates a link between the families and their entourage which went beyond death."
As they reported online today in Science Advances, researchers in Italy, Germany, and elsewhere used targeted enrichment and Illumina sequencing to profile roughly a million SNPs per person in samples from 13 early Medieval individuals — 10 adults and three infants — from the Alemannic burial site near the city of Niederstotzingen. The site contained individual as well as mass graves, they noted, along with the remains of several horses and decorations linked to cultures in France, northern Italy, and Byzantium.
Based on the genetic data it generated, the team saw signs of sex-biased burial, since at least 11 of the individuals were male. But while five of the individuals appeared to be first- or second-degree relatives, the decorative features on their graves were culturally diverse. Likewise, the site included individuals that clustered genetically with present-day populations in northern or western Europe, and with more distant populations in southern Europe or the Mediterranean.
"The genetic makeup of the individuals shares no observable pattern with their orientation in the burial or the cultural association of their grave goods, with the five related individuals buried with grave goods associated with three diverse cultural origins," O'Sullivan and his co-authors explained. "These findings support the idea that not only were kinship and fellowship held in equal regard: Diverse cultural appropriation was practiced among closely related individuals as well."
Using DNA isolated from tooth samples at the burial site, the researchers targeted 1.24 million autosomal SNPs and mitochondrial sequences using a 1240k in-solution capture approach. After sequencing the libraries with Illumina HiSeq 2500, NextSeq, or HiSeq 4000 platforms, they had sufficient data to show 11 or more of the individuals were likely male.
The team identified a range of mitochondrial haplotypes and at least Y chromosome lineages at the site. The five related individuals buried there clustered genetically with modern-day populations in northern, eastern, and central Europe based on comparisons with variants in the Human Origins Database, the researchers reported. The remaining three individuals were unrelated, and included two individuals with closer genetic ties to southern Europe or the eastern Mediterranean.
These and other findings prompted the researchers to speculate that at least some of the individuals may have been incorporated into the Alemannic tribes to act as warriors — a notion supported by the elaborate burials at the site.
"The burial of three unrelated individuals in multiple graves beside the rest of the cohort would imply that this Alemannic group buried their dead based on a combination of familial ties and fellowship," the authors wrote. "One explanation could be that they were adopted as children from another region to be trained as warriors, which was a common practice at the time these children were raised with equal regard in the familia."