NEW YORK (GenomeWeb) – Sequencing samples from two ancient cemeteries has given researchers a glimpse into the movements and social organization of the ancient Longobards, who ruled a large swathe of Italy between about 570 AD and 775 AD.
The time between the 4th and 8th centuries following the decline of the Western Roman Empire was a socioeconomically and culturally transformational era in Europe called the Migration Period. During this time, the Longobards — also known as the Lombards — invaded Italy from Pannonia in what is now Hungary, but there are few reliable records from the era.
Researchers led by Stony Brook University's Krishna Veeramah collected 63 samples from two cemeteries, one in Hungary and one in northern Italy, that have been linked to the Longobards. As they reported today in Nature Communications, the researchers analyzed DNA isolated from those samples, and found that each cemetery was focused around one large pedigree and that the individuals' genetic backgrounds may have influenced their social status.
"It looks like both these cemeteries organized themselves around one or two large groups of biologically related kin, with the vast majority of these individuals being men," Veeramah said in a statement. "In addition, these related individuals tended to share the northern/central genetic ancestry associated with rich grave goods."
He and his colleagues extracted DNA from a respective 39 and 24 samples collected from the Szólád cemetery in Hungary and the Collegno cemetery in Italy for analysis, including Illumina sequencing. They were able to perform whole-genome sequencing to a mean coverage of 11.3X for 10 Szólád samples, and the remaining 53 samples underwent in-solution capture targeting 1.2 million SNPs.
A principal components analysis of the Szólád and Collegno samples, in conjunction with modern references, showed that the ancient samples harbored genetic ancestry that overlaps with that of modern Europeans.
However, the researchers noted that the genetic ancestry of modern Hungarians and the Szólád samples do not cluster together, and neither do the modern Italian and the Collegno samples. The ancient samples instead exhibited a diverse distribution with two primary central/northern and southern groups.
Analysis of the Szólád and Collegno samples using the Admixture algorithm indicated that their major ancestral genetic component was similar to what's seen today among northern and central Europeans, followed by an ancestral genetic component found among Toscani Italians.
The high level of northern and central Europeans ancestry seen in the Szólád and Collegno samples is unusual, the researchers said. They further found that individuals with a higher degree of northern/central ancestry were more likely to be buried with grave goods like swords or beaded jewelry than individuals with more southern ancestry. In addition, isotopic analysis revealed that individuals with more with grave goods tended to eat a diet higher in animal protein.
At the same time, the researchers uncovered related individuals among their cemetery samples. Within the Szólád cemetery, the researchers found four kindreds, including one large one that with 10 individuals, spanning three generations. Similarly, the researchers uncovered three kindreds among the Collegno samples, with, again, a large 10-member lineage. These lineages, the researchers noted, tended to have northern/central European ancestry and be buried with grave goods.
"This appears to suggest that these particular communities contained a mix of individuals with different genetic backgrounds, that they were aware of these differences, and that it likely influenced their social identity," co-author Patrick Geary, from the Institute for Advanced Study, said in a statement.
Isotopic analysis of the Szólád samples uncovered diverse signatures, suggesting that not all the individuals originated in the area and that not all came from the same outside region. By contrast, the Collegno samples were more likely to have local isotope samples. This suggested to the researchers that the Szólád population might have been more transient than the Collegno one, and that those with more northern ancestry were migrants to the region while those with more southern ancestry were local.
The researchers cautioned, however, that more samples from more cemeteries need to be analyzed.