Biology subjects

Kassadjikova, K.

Publications and source records attributed to Kassadjikova, K..

5 recordsLinked to original sources

bioRxiv2026

On the Edge of Empire: Paleogenomic Insights into Roman Dacia

The Roman province of Dacia, located north of the Danube frontier, represented a key zone of cultural and demographic interaction during the Imperial period. However, the biological impact of Roman colonization in this region has not been characterized using genomic data. Here, we analyze genome-wide data from 34 individuals recovered from the Apulum-Dealul Furcilor necropolis, one of the largest funerary complexes in Roman Dacia. The genome-wide data reveal pronounced genetic heterogeneity within this population, reflecting its position at the intersection of Eastern Europe, the Mediterranean, and West Asia. Notably, we observe a sex-biased pattern of ancestry. Female individuals show stronger affinities to Eastern European, Steppe, and Caucasus-associated populations, suggesting the persistence of local or regionally connected genetic lineages. In contrast, male individuals display closer genetic relationships with Mediterranean and North African groups, including populations associated with Roman and Punic contexts, indicating male-mediated gene flow linked to long-distance mobility. These findings highlight the complex demographic processes shaping Roman frontier communities, where local and incoming populations were integrated through asymmetric social dynamics. Our results provide genomic evidence consistent with sex-biased admixture in Roman Dacia and underscore the role of frontier regions as hubs of genetic and cultural interaction within the Roman Empire.

genomics↗

bioRxiv2026

The Genomic Legacy of the Norman Conquest in Rural England

The Norman Conquest of 1066 CE reshaped the political and cultural landscape of England, yet its demographic consequences remain poorly understood, particularly outside elite and urban contexts where historical evidence is concentrated. Here, we investigate the population history of a rural English community spanning the Conquest using genome-wide ancient DNA from the Priory Orchard site, a cemetery in Godalming (Surrey) in use between the 9th and early 13th centuries CE. We generated genomic data from 78 individuals and established radiocarbon dates for 98 individuals from the site. Population genetic analyses place Priory Orchard individuals within the genetic continuum of early medieval populations from the North Sea region. Ancestry modelling indicates that this rural community carried substantial Scandinavian/Viking-related ancestry alongside a persistent Saxon-related component and a smaller French-related contribution. However, stratifying individuals by date, before and after 1066 CE, reveals no clear genome-wide discontinuity across the Conquest horizon, suggesting demographic continuity through this crucial political and social transition. This pattern is consistent with historical and archaeological evidence indicating that many of the most visible transformations following the Conquest occurred primarily among the elite. Our results provide the first genomic perspective on communities living through the Norman Conquest and indicate that rural southern England saw persistent migration links with other areas facing the North Sea rather than abrupt population replacement.

genetics↗

bioRxiv2025

Palaeogenomics reveals 1,500 years of population history of the peoples of the Chonos Archipelago, Chile.

The Chonos archipelago, located in northwestern Chilean Patagonia, was historically inhabited by an Indigenous sea-faring population known to the European colonists as the "Chono". Previous research has contextualized the human occupation of this region with radiocarbon dates and ancient mitochondrial genomes, offering a partial perspective on the history of its inhabitants. Here we present a paleogenomic analysis of 20 ancient human individuals from 6 archaeological sites, dated between 1,600-50 years before present (BP). We successfully captured over 100,000 SNPs from 15 of 20 individuals and recovered 12 full mitogenomes. All individuals presented unadmixed Indigenous South American ancestry and formed a separated genetic cluster relative to other ancient and modern South American genomes, indicating a unique Chonos ancestry. This Chonos ancestry falls within a broader cluster of late-Holocene Patagonian ancestry, most similar to the Kawesqar peoples who neighbour to the south. Within the Chonos, we distinguish a northern and southern ancestry cluster. The northern Chonos cluster exhibits some genetic connections to the present-time inhabitants of the neighbouring island of Chiloe, who are connected to Huilliche Indigenous history. Our findings reveal a point of contact between southern Chonos/Patagonian ancestry to the south and Mapuche ancestry to the north, and confirm that sea-faring subsistence was a knowledge transferred between Patagonian peoples.

genomics↗

bioRxiv2023

Allelic bias when performing in-solution enrichment of ancient human DNA

In-solution hybridisation enrichment of genetic variation is a valuable methodology in human paleogenomics. It allows enrichment of endogenous DNA by targeting genetic markers that are comparable between sequencing libraries. Many studies have used the 1240k reagent--which enriches 1,237,207 genome-wide SNPs--since 2015, though access was restricted. In 2021, Twist Biosciences and Daicel Arbor Biosciences independently released commercial kits that enabled all researchers to perform enrichments for the same 1240k SNPs. We used the Daicel Arbor Biosciences Prime Plus kit to enrich 132 ancient samples from three continents. We identified a systematic assay bias that increases genetic similarity between enriched samples and that cannot be explained by batch effects. We present the impact of the bias on population genetics inferences (e.g., Principal Components Analysis, [f]-statistics) and genetic relatedness (READ). We compare the Prime Plus bias to that previously reported of the legacy 1240k enrichment assay. In [f]-statistics, we find that all Prime-Plus-generated data exhibit artefactual excess shared drift, such that within-continent relationships cannot be correctly determined. The bias is more subtle in READ, though interpretation of the results can still be misleading in specific contexts. We expect the bias may affect analyses we have not yet tested. Our observations support previously reported concerns for the integration of different data types in paleogenomics. We also caution that technological solutions to generate 1240k data necessitate a thorough validation process before their adoption in the paleogenomic community.

genomics↗

bioRxiv2020

A paleogenetic perspective of the Sabana de Bogota (Northern South America) population history over the Holocene (9000 - 550 cal BP)

ABSTRACTOn the basis of distinct lines of evidence, detailed reconstructions of the Holocene population history of the Sabana de Bogota (SB) region, Northern South America, have been performed. Currently, there exist two competing models that support temporal continuity or, alternatively, divergence. Despite recent research that lends support to the population discontinuity model, several discrepancies remain, calling for other kinds of evidences to be explored for a more detailed picture of Holocene biocultural evolution. In this study, we analyze the mitochondrial genetic diversity of 30 individuals (including 15 newly reported complete mitochondrial genomes) recovered from several archaeological sites spanning from the late Pleistocene (12,164 cal BP) until the final late Holocene (2,751 cal BP) along with published data from the region dating [~]9,000-550 cal BP in order to investigate diachronic genetic change. Genetic diversity and distance indices were calculated, and demographic models tested in an approximate Bayesian computation (ABC) framework to evaluate whether patterns of genetic affinities of the SB prehispanic populations support genetic continuity or discontinuity. The results show that mitochondrial genomes of the complete dataset fall within the Native American haplogroups A2, B2, C1b, D1 and D4h3a. Haplotype and nucleotide diversity declined over time with further evidence of genetic drift and remarkable reduction of genetic diversity during the final late Holocene. Inter-population distances and the exact test of population differentiation, as well as demographic simulations show no population differentiation and population continuity over time. Consequently, based on the analyzed data, we cannot reject the genetic continuity in the SB region as a plausible population history scenario. However, the restriction of the analyses to the Hyper Variable Region 1 of the mitochondrial genome, and the very low sample size both constitute significant limitations to infer evolutionary history.

genetics↗