Rewriting History: Advanced Genetic Analysis Uncovers Ancient Ancestry Shifts in Europe

By Dr. Chinta SidharthanReviewed by Lily Ramsey, LLMJan 9 2025

Understanding historical human migrations and genetic admixtures provides key insights into the formation of modern populations. Recent advancements in ancient genome sequencing have allowed researchers to trace ancestry and reconstruct demographic events with unprecedented precision.

In a recent study published in Nature, a team of evolutionary biologists and archaeologists examined over 1,500 ancient genomes to study the migrations and genetic interactions in early medieval Europe.

The findings revealed high-resolution ancestry patterns from 500 BCE to 1000 CE and identified Scandinavian-related ancestry movements, their subsequent mixing across Europe, and major genetic shifts in Viking Age Scandinavia.

​​​​​​​Study: High-resolution genomic history of early medieval Europe. Image Credit: Billion Photos/Shutterstock.com

Background

The analysis of ancient deoxyribonucleic acid (DNA) has transformed our understanding of past migrations and genetic exchanges and enabled us to form detailed reconstructions of human history.

However, studying historical periods with minimal genetic differentiation, as seen among human populations, remains challenging. For example, groups in northern and central Europe from the Iron Age onward share closely related ancestries, making it difficult to discern migration and interaction patterns using traditional genetic methods.

Previous research has shown that the Viking Age and medieval periods encompassed numerous migrations, but distinguishing these ancestries has been hindered by limited resolution in data.

Moreover, existing methods, such as f-statistics, provide robust models but lack the power to resolve fine-scale genetic events involving closely related populations, highlighting the need for temporal frameworks to enhance the resolution of genetic ancestry studies.

The current study

The present study employed an innovative method called Twigstats to perform time-stratified ancestry analysis on 1,556 ancient genomes from Europe.

Twigstats incorporates inferred genealogies and focuses on recent coalescence or merging events to enhance the statistical power of traditional f-statistics. This approach calculates ancestry using branches of genealogical trees, enabling researchers to isolate recent genetic changes while minimizing noise from older coalescences.

The researchers used geographical and temporal contexts, including Iron Age Scandinavia, Roman-era populations, and early medieval groups, to categorize the samples from early medieval Europe into model ancestry sources.

Hierarchical clustering and pairwise clade testing were also conducted to validate the selection of ancestry sources. Fine-scale genetic structures were identified using non-parametric multidimensional scaling, which revealed close affinities within regional populations.

The study also incorporated qpAdm models, which are exploratory archaeogenetic models used to estimate admixture proportions and resolve ancestry sources for various populations.

To test model robustness, the researchers compared results using genealogical branches with those derived from conventional single nucleotide polymorphism (SNP)-based methods.

The analysis was further validated through simulations, which led to substantial improvements in detecting and quantifying recent events of admixture or genetic intermingling.

Additionally, the researchers constructed time transects for specific regions to chart the ancestry changes across millennia. This comprehensive framework allowed them to map genetic shifts associated with Scandinavian-related ancestries and their interactions with central and southern European populations during the Viking Age.

Major findings

The study revealed that genetic ancestries in Europe underwent significant transformations between 500 BCE and 1000 CE. It identified two expansions of Scandinavian-related ancestry across Europe during the first millennium CE.

In the early centuries, these ancestries appeared across eastern, western, and central Europe and were associated with groups such as the Goths.

By the second half of the millennium, evidence suggested a decline in the presence of distinct Scandinavian-related ancestries, which were replaced by substantial admixture with local populations.

In Scandinavia, major genetic shifts occurred around 800 CE, coinciding with the early Viking Age. The individuals from this period exhibited significant ancestry from central Europe, a pattern not observed in earlier Iron Age populations.

The study also highlighted regional differences in genetic mixing within Scandinavia. Southern areas, especially Denmark, showed higher proportions of central European-related ancestry, whereas northern regions retained greater continuity with earlier Scandinavian ancestries.

Furthermore, regional analyses revealed ancestry shifts in Poland, where early medieval populations exhibited a mix of Scandinavian, Roman Iron Age, and Bronze Age ancestries.

Similarly, early medieval populations in Slovakia and Hungary showed evidence of Scandinavian-related ancestry. They were linked to groups such as the Longobards, a Germanic tribe also known as the Lombards.

The study also revealed that in Britain, Scandinavian-related ancestry was detected before the fifth century CE, with substantial influxes during the Anglo-Saxon migrations and Viking Age. The study’s high-resolution approach provided new insights into the timing and scale of migrations, admixture events, and genetic transformations across Europe.

Conclusions

Overall, the use of the novel Twigstats method uncovered several interesting findings about the genetic history of early medieval Europe and revealed significant ancestry movements and transformations.

Using ancient genomes, the researchers identified Scandinavian-related expansions and subsequent admixture events that reshaped the European genetic landscapes.

Furthermore, these findings highlighted the complex interplay of migrations and local interactions during the Iron, Roman, and Viking Ages. This work also emphasized the importance of high-resolution analyses in unraveling the intricate genetic history of human populations.