Biology subjects

Llanos-Lizcano, A.

Publications and source records attributed to Llanos-Lizcano, A..

3 recordsLinked to original sources

bioRxiv2026

Genomic impact of the second plague pandemic on three human populations

The second plague pandemic (early 14th-early 19th centuries), which was caused by Yersinia pestis, had a profound demographic, socio-economic and cultural impact across Eurasia and North Africa. Many regions in Europe and the Middle East are estimated to have lost 40-60% of their human populations, with some areas suffering even higher mortality. Whether exposure to Y. pestis drove strong positive selection on protective genetic variants in the human genome, and how it shaped migration patterns, remains debated, despite several recent studies based on ancient DNA. Here, we analyse a markedly larger, higher coverage, and geographically diverse dataset based on shotgun sequencing of genomes from 529 ancient individuals to a mean depth 8.8x dating to either before or after the arrival of the pandemic at three sites in northern Europe: Trondheim (Norway), Lund (Sweden) and Vilnius (Lithuania). Genome-wide scans for signatures of selection provide no evidence for strong positive selection acting on specific genetic variants driven by Y. pestis exposure: we neither replicate selection signatures reported by previous studies nor identify new genome-wide significant candidates. However, for all three sites, we observe evidence for a reduction in long-range immigration, indicated by a drop in the diversity of ancestry that followed the arrival of Y. pestis and broadly coincided with the end of the Viking Age, Christianisation and the onset of the Little Ice Age. Our results shed important light on the demographic impact of major sociohistorical changes that occurred during the late Medieval period in Scandinavia and the Baltic region and link Christianisation to increased diversity in ancestry before the pandemic.

genomics↗

bioRxiv2025

Genetic insights into Iron Age Saka culture: Ancient DNA analysis of the Boz-Barmak burial ground, Kyrgyzstan

The nomadic cultures of the Iron Age played an important role in shaping the genetic and cultural landscape of Eurasian populations. Yet despite its key geographical location, the Central Eurasian region remains underrepresented in ancient DNA studies of humans. We address this gap through genomic analysis of 12 individuals from the Boz-Barmak burial site in Kyrgyzstan associated with Saka pastoralists (4th-2nd centuries BCE), 9 of which yielded low-coverage genomes. Genetic clustering analysis placed these individuals within the genetic variation of ancient and modern Central Eurasian and Siberian populations. We found no evidence of first-degree relatives in a kinship analysis, however a network of second- and third-degree relationships seems to be present. Notably, all male individuals share the same Y-chromosomal haplotype, common in present-day Kyrgyz and Tajik groups, while mitochondrial DNA showed comparably high diversity, with distinct haplogroups observed across the analysed individuals. These findings are in line with archaeological and ethnographic evidence of patrilocality in Early Iron Age Saka, where male lineages remained stable across generations, while female mobility contributed to genetic diversity. Our study complements our understanding of the interplay between kinship, social organization and population history in nomadic cultures.

genomics↗

bioRxiv2024

A complete mitochondrial genome of a Roman-era Plasmodium falciparum

Malaria has historically been one of the leading infection-related causes of death in human populations. To this day, it continues to pose a significant public health threat in African countries, particularly among children. Humans are affected by five Plasmodium species, with Plasmodium falciparum being the most lethal. The study of pathogenic DNA from ancient human remains has been vital in understanding the origin, evolution, and virulence of human-infecting pathogens. However, there have been no complete pre-20th century mitochondrial DNA (mtDNA) or genomic sequences of Plasmodium falciparum reported to date. This gap in knowledge makes it difficult to understand the genetic dynamics of this pathogen in the past. The difficulty in identifying ancient malaria cases through bioarchaeology and the infrequent presence of Plasmodium DNA in ancient bones contribute to these limitations. Here, we present the first complete mtDNA genome of P. falciparum recovered from an archaeological skeleton (a 2nd century CE Roman individual from Italy). The study of the 43-fold mtDNA genome supports the hypothesis of an Indian origin for P. falciparum in Europe and provides evidence for the genetic continuity of this lineage over the past 2,000 years. Additionally, our research highlights that extensive sampling may be necessary for malaria screening to gain insights into the evolution of this vector-borne disease from archaeological samples.

genomics↗