A genetic perspective on Longobard-Era migrations

Abstract

From the first century AD, Europe has been interested by population movements, commonly known as Barbarian migrations. Among these processes, the one involving the Longobard culture interested a vast region, but its dynamics and demographic impact remains largely unknown. Here we report 87 new complete mitochondrial sequences coming from nine early-medieval cemeteries located along the area interested by the Longobard migration (Czech Republic, Hungary and Italy). From the same areas, we sampled necropoleis characterized by cultural markers associated with the Longobard culture (LC) and coeval burials where no such markers were found, or with a chronology slightly preceding the presumed arrival of the Longobards in that region (NLC). Population genetics analysis and demographic modeling highlighted a similarity between LC individuals, as reflected by the sharing of quite rare haplogroups and by the degree of genetic resemblance between Hungarian and Italian LC necropoleis estimated via a Bayesian approach, ABC. The demographic model receiving the strongest statistical support also postulates a contact between LC and NLC communities, thus indicating a complex dynamics of admixture in medieval Europe.

Fig. 1

Geographical and genetic relationship between LC and NLC populations. Here and through the other figures LC cemeteries are represented by a circle while NLC ones are indicated by a square. Pie charts representing the frequencies of the major haplogroups in the populations. The size of the charts is proportional to the number of samples inside each necropolis

Fig. 2

Alternative models of relationship between LC and NLC populations. a Admixture, b continuity, c recent origin, d recent origin + admixture. Continuous lines represent populations that were included in the simulations while dotted lines characterize ghost populations

Fig. 3

Median-joining network of the newly sequenced individuals. The size of the circles is proportional to the number of samples carrying a specific haplotype, and the background shading indicates the affiliation of the lineages to the major haplogroups

Fig. 4

PCA based on haplogroup frequencies of LC and medieval populations. Circles represent LC necropoleis, whereas diamonds characterize the 11 medieval European populations