Biology subjects

Lamnidis, T. C.

Publications and source records attributed to Lamnidis, T. C..

7 recordsLinked to original sources

bioRxiv2025

High resolution analysis of population structure using rare variants

Various statistical methods have been developed to identify population structure from genetic data, including F-statistics, which measure the average correlation in allele frequency differences between two pairs of populations. However, the SNPs analyzed with F-statistics are often limited to those found as part of microarrays or, in the case of ancient DNA, to SNP capture panels, which are those within the common allele frequency band. Recent advances in sequencing technology increasingly allow generating whole-genome sequencing data, both ancient and modern, which not only enable querying nearly every base of the genome, but also contain numerous rare variants. Rare variants, with their more population-specific distribution, allow detection of population structure with much finer resolution than common variants - an opportunity that has so far been under-exploited. Here, we develop a new statistical method, RAS (Rare Allele Sharing), for summarizing rare allele frequency correlations, similar to F-statistics but with flexible ascertainment on allele frequencies. We test RAS on both published and simulated data and find that RAS has better resolution in distinguishing populations, with appropriate ascertainment. Leveraging this, we further develop the use of RAS to compute ancestry proportions with higher accuracy than existing methods, in cases of closely-related source populations. We implemented the new statistical methods as an R package and a command line tool. In summary, our method can provide new perspectives to identify and model population structure, allowing us to understand more subtle relationships among populations in the recent human past.

genetics↗

bioRxiv2024

The Genetic History of the South Caucasus from the Bronze to the Early Middle Ages: 5000 years of genetic continuity despite high mobility

Archaeological and archaeogenetic studies have highlighted the pivotal role of the Caucasus region throughout prehistory, serving as a central hub for cultural, technological, and linguistic innovations. However, despite its dynamic history, the critical area between the Greater and Lesser Caucasus mountain ranges, mainly corresponding to modern-day Georgia, has received limited attention. Here, we generated an ancient DNA time transect consisting of 219 individuals with genome-wide data from 47 sites in this region, supplemented by 97 new radiocarbon dates. Spanning from the Early Bronze Age 5000 years ago to the so-called Migration Period that followed the fall of the Western Roman Empire, we document a largely persisting local gene pool that continuously assimilated migrants from Anatolia/Levant and the populations of the adjacent Eurasian steppe. More specifically, we observe these admixture events as early as the Middle Bronze Age. Starting with Late Antiquity (late first century AD), we also detect an increasing number of individuals with more southern ancestry, more frequently associated with urban centers - landmarks of the early Christianization in eastern Georgia. Finally, in the Early Medieval Period starting 400 AD, we observe genetic outlier individuals with ancestry from the Central Eurasian steppe, with artificial cranial deformations (ACD) in several cases. At the same time, we reveal that many individuals with ACD descended from native South Caucasus groups, indicating that the local population likely adopted this cultural practice.

genetics↗

bioRxiv2024

Poseidon - A framework for archaeogenetic human genotype data management

1The study of ancient human genomes, archaeo- or palaeogenetics, has accelerated in the last ten years, with now thousands of new ancient genomes being released each year. Operating at the interface of genetics, anthro-pology and archaeology, this data includes features from all three fields, including rich meta- and context-data, for example regarding spatiotemporal provenience. While archives and standards for genetic sequencing data al-ready exist, no such infrastructure exists for combined genetic and meta-data that could ensure FAIR principles across the field. Here, we present Poseidon, a framework for open and FAIR data handling in archaeogenetics, including a specified package format, software tools, and public, community-maintained online archives. Poseidon emphasises human- and machine-readable data storage, the development of convenient and interoperable command line software, and a high degree of source granularity to elevate the original data publication to the main unit of long-term curation.

genetics↗

bioRxiv2021

Ancient genomes reveal long range influence of the site and culture of Tiwanaku

Tiwanaku was a civilization that flourished in the Lake Titicaca Basin (present-day Bolivia) between 500 and 1000 CE. At its apogee, Tiwanaku controlled the lakes southern shores and influenced certain areas of the Southern Andes. There is a considerable amount of archaeological and anthropological data concerning the Tiwanaku culture; however, our understanding of the population of the site of Tiwanaku is limited. To understand the population dynamics at different stages of the Tiwanaku cultural development, we analyzed 17 low-coverage genomes from individuals dated between 300 and 1500 CE. We found that the population from the Lake Titicaca Basin remained genetically unchanged throughout more than 1200 years, indicating that significant cultural and political changes were not associated with large scale population movements. In contrast, individuals excavated from Tiwanakus ritual core were highly heterogeneous, some with genetic ancestry from as far away as the Amazon, supporting the proposition of foreign presence at the site. However, mixed-ancestry individuals presence suggests they were local descendants of incomers from afar rather than captives or visiting pilgrims. A number of human offerings from the Akapana Platform dating to ca. 950 CE mark the end of active construction and maintenance of the monumental core and the wane of Tiwanaku culture. Significance StatementTiwanaku was an important pre-Inca polity in South America and an example of primary social complexity on par with civilizations in the Indus and Nile river valley. Flourishing between 500 and 1000 CE, Tiwanaku exercised control in the south Titicaca basin and influenced a vast area in southern Peru, Bolivia, and northern Chile. Comprehensive archeological studies provided information about the rise, expansion, and fall of the Tiwanaku culture, but little is known about the monumental sites population. To address this lacuna, we generated low coverage genomes for 17 individuals, revealing that while the Titicaca basins residential population was homogenous, the individuals excavated from the ritual core of Tiwanaku drew their ancestry from distant regions.

genomics↗

bioRxiv2020

Reproducible, portable, and effcient ancient genome reconstruction with nf-core/eager

The broadening utilisation of ancient DNA to address archaeological, palaeontological, and biological questions is resulting in a rising diversity in the size of laboratories and scale of analyses being performed. In the context of this heterogeneous landscape, we present nf-core/eager, an advanced and entirely redesigned and extended version of the EAGER pipeline for the analysis of ancient genomic data. This Nextflow pipeline aims to address three main themes: accessibility and adaptability to different computing configurations, reproducibility to ensure robust analytical standards, and updating the pipeline to the latest routine ancient genomic practises. This new version of EAGER has been developed within the nf-core initiative to ensure high-quality software development and maintenance support; contributing to a long-term lifecycle for the pipeline. nf-core/eager will assist in ensuring that ancient DNA sequencing data can be used by a diverse range of research groups and fields.

bioinformatics↗

bioRxiv2018

Ancient Fennoscandian genomes reveal origin and spread of Siberian ancestry in Europe

European history has been shaped by migrations of people, and their subsequent admixture. Recently, evidence from ancient DNA has brought new insights into migration events that could be linked to the advent of agriculture, and possibly to the spread of Indo-European languages. However, little is known so far about the ancient population history of north-eastern Europe, in particular about populations speaking Uralic languages, such as Finns and Saami. Here we analyse ancient genomic data from 11 individuals from Finland and Northwest Russia. We show that the specific genetic makeup of northern Europe traces back to migrations from Siberia that began at least 3,500 years ago. This ancestry was subsequently admixed into many modern populations in the region, in particular populations speaking Uralic languages today. In addition, we show that ancestors of modern Saami inhabited a larger territory during the Iron Age than today, which adds to historical and linguistic evidence for the population history of Finland.

genomics↗

bioRxiv2017

Paleo-Eskimo genetic legacy across North America

Paleo-Eskimos were the first people to settle vast regions of the American Arctic around 5,000 years ago, and were subsequently joined and largely displaced around 1,000 years ago by ancestors of the present-day Inuit and Yupik. The genetic relationship between Paleo-Eskimos and Native American populations remains uncertain. We analyze ancient and present-day genome-wide data from the Americas and Siberia, including new data from Alaskan Inupiat and West Siberian populations, and the first genome-wide DNA from ancient Aleutian Islanders, ancient northern Athabaskans, and a 4,250-year-old individual of the Chukotkan Ust'-Belaya culture. Employing new methods based on rare allele and haplotype sharing as well as established methods based on allele frequency correlations, we show that Paleo-Eskimo ancestry is widespread among populations who speak Na-Dene and Eskimo-Aleut languages. Using phylogenetic modelling with allele frequency correlations and rare variation, we present a comprehensive model for the complex peopling of North America.

genetics↗