Despite the increase in our knowledge about the factors that shaped the genetic structure of the human population in Europe, the demographic processes that occurred during and after the Early Bronze Age (EBA) in Central-East Europe remain unclear. To fill the gap, we isolated and sequenced DNAs of 60 individuals from Kowalewko, a bi-ritual cemetery of the Iron Age (IA) Wielbark culture, located between the Oder and Vistula rivers (Kow-OVIA population). The collected data revealed high genetic diversity of Kow-OVIA, suggesting that it was not a small isolated population. Analyses of mtDNA haplogroup frequencies and genetic distances performed for Kow-OVIA and other ancient European populations showed that Kow-OVIA was most closely linked to the Jutland Iron Age (JIA) population. However, the relationship of both populations to the preceding Late Neolithic (LN) and EBA populations were different. We found that this phenomenon is most likely the consequence of the distinct genetic history observed for Kow-OVIA women and men. Females were related to the Early-Middle Neolithic farmers, whereas males were related to JIA and LN Bell Beakers. In general, our findings disclose the mechanisms that could underlie the formation of the local genetic substructures in the South Baltic region during the IA.

Background The appearance of Slavs in East-Central Europe has been the subject of an over 200-year debate driven by two conflicting hypotheses. The first assumes that Slavs came to the territory of contemporary Poland no earlier than the sixth century CE; the second postulates that they already inhabited this region in the Iron Age (IA). Testing either hypothesis is not trivial given that cremation of the dead was the prevailing custom in Central Europe from the late Bronze Age until the Middle Ages (MA). Results To address this problem, we determined the genetic makeup of representatives of the IA Wielbark- and MA Slav-associated cultures from the territory of present-day Poland. The study involved 474 individuals buried in 27 cemeteries. For 197 of them, genome-wide data were obtained. We found close genetic affinities between the IA Wielbark culture-associated individuals and contemporary to them and older northern European populations. Further, we observed that the IA individuals had genetic components which were indispensable to model the MA population. Conclusions The collected data suggest that the Wielbark culture-associated IA population was formed by immigrants from the north who entered the region of contemporary Poland most likely at the beginning of the first millennium CE and mixed with autochthons. The presented results are in line with the hypothesis that assumes the genetic continuation between IA and MA periods in East-Central Europe.

Metabolic gene clusters (MGCs) are groups of genes involved in a common biosynthetic pathway. They are frequently formed in dynamic chromosomal regions, which may lead to intraspecies variation and cause phenotypic diversity. We examined copy number variations (CNVs) in four Arabidopsis thaliana MGCs in over one thousand accessions with experimental and bioinformatic approaches. Tirucalladienol and marneral gene clusters showed little variation, and the latter was fixed in the population. Thalianol and especially arabidiol/baruol gene clusters displayed substantial diversity. The compact version of the thalianol gene cluster was predominant and more conserved than the noncontiguous version. In the arabidiol/baruol cluster, we found a large genomic insertion containing divergent duplicates of the CYP705A2 and BARS1 genes. The BARS1 paralog, which we named BARS2, encoded a novel oxidosqualene synthase. The expression of the entire arabidiol/baruol gene cluster was altered in the accessions with the duplication. Moreover, they presented different root growth dynamics and were associated with warmer climates compared to the reference-like accessions. In the entire genome, paired genes encoding terpene synthases and cytochrome P450 oxidases were more variable than their nonpaired counterparts. Our study highlights the role of dynamically evolving MGCs in plant adaptation and phenotypic diversity.

The origin of the Piast dynasty is a matter of lively discussions and disputes. At least a few controversial hypotheses exist, but their credibility is difficult to assess due to the scarcity of written as well as material sources, especially from the time of Polish state formation. Life sciences, however, can support history and archeology. Application of genetic tests, used earlier mainly in forensic laboratories, enabled identification of the remains of King Richard III, the Romanov dynasty members and Nicolaus Copernicus. Contemporary DNA studies, based on next generation DNA sequencing, outreach the narrow area of known markers such as mitochondrial DNA (mtDNA) and selected regions of Y chromosome. Although ancient DNA (aDNA), extracted from remains, is usually highly degraded and contaminated with genetic material of microorganisms, there are methods which allow for the analysis of such material and retrieval of information about origin, kinship and some phenotypic features of an individual. Genetic studies of the Piast dynasty, a subject of our research project, have to deal with numerous difficulties. In or der to gain access to bone samples, we need to meet a number of formal requirements. Moreover, despite the existence of available abundant documentation on the Piast burials, the actual situation is not always consistent with the written sources. Our first experiences show how difficult it is to localize the remains, identify them and extract DNA of sufficient quality.

Archaeogenomis is a recently developed interdisciplinary research field that utilizes advanced molecular biology techniques, especially DNA sequencing, to study the history of biological species, including humans. Analyses of ancient genomes provide independent information about human ancestors and their migrations, allowing researchers to uncover history of mankind. Here, we present the fundamental principles of archaeogenomics and its application in the studies of biological history of the populations inhabiting central-east Europe.