Biology subjects

Meshveliani, T.

Publications and source records attributed to Meshveliani, T..

3 recordsLinked to original sources

bioRxiv2023

A minimally-invasive method for ancient DNA sampling of Prehistoric bone and antler tools and hunting weapons

Internal and external bony tissues from diverse mammalian taxa are one of the primary animal raw materials exploited for technical and symbolic purposes by Eurasian Upper Palaeolithic hunter-gatherers. Identifying the source species used for osseous raw material is critical to gain insights into these populations behaviour, technology, and subsistence. The study of osseous tools has advanced in the last few years by combining archaeological and biomolecular methods. Ancient genomics opens many new analytical opportunities. Ancient DNA (aDNA) can provide a wealth of information about the animal sources of these objects. Unfortunately, aDNA analyses often involve destructive sampling. Here, we develop and apply a minimally-invasive aDNA sampling method for an assemblage of 42 prehistoric hunting weapons and tools from various Eurasian archaeological sites. We evaluated the impact of our approach on the specimens visually, microscopically and through Micro-CT scans. The surface impacts are marginal, ranging from 0.3-0.4 mm. Using a custom-made DNA capture kit for 54 mammalian species, we obtained sufficient aDNA to identify the taxa of 33% of the objects. For one of the tools, we recovered enough endogenous aDNA to infer the genetic affinities of the individual. Our results also demonstrate that ancient antler, one of the primary raw materials used during a large part of prehistory, is a reliable source of aDNA. Our minimally-invasive aDNA sampling method is therefore effective while preserving osseous objects for potential further analyses: morphometric, technical, genetic, radiometric and more.

genomics↗

bioRxiv2020

An open-sourced bioinformatic pipeline for the processing of Next-Generation Sequencing derived nucleotide reads: Identification and authentication of ancient metagenomic DNA.

Bioinformatic pipelines optimised for the processing and assessment of metagenomic ancient DNA (aDNA) are needed for studies that do not make use of high yielding DNA capture techniques. These bioinformatic pipelines are traditionally optimised for broad aDNA purposes, are contingent on selection biases and are associated with high costs. Here we present a bioinformatic pipeline optimised for the identification and assessment of ancient metagenomic DNA without the use of expensive DNA capture techniques. Our pipeline actively conserves aDNA reads, allowing the application of a bioinformatic approach by identifying the shortest reads possible for analysis (22-28bp). The time required for processing is drastically reduced through the use of a 10% segmented non-redundant sequence file (229 hours to 53). Processing speed is improved through the optimisation of BLAST parameters (53 hours to 48). Additionally, the use of multi-alignment authentication in the identification of taxa increases overall confidence of metagenomic results. DNA yields are further increased through the use of an optimal MAPQ setting (MAPQ 25) and the optimisation of the duplicate removal process using multiple sequence identifiers (a 4.35-6.88% better retention). Moreover, characteristic aDNA damage patterns are used to bioinformatically assess ancient vs. modern DNA origin throughout pipeline development. Of additional value, this pipeline uses open-source technologies, which increases its accessibility to the scientific community.

genomics↗

bioRxiv2018

Paleolithic DNA from the Caucasus reveals core of West Eurasian ancestry

The earliest ancient DNA data of modern humans from Europe dates to [~]40 thousand years ago1-4, but that from the Caucasus and the Near East to only [~]14 thousand years ago5,6, from populations who lived long after the Last Glacial Maximum (LGM) [~]26.5-19 thousand years ago7. To address this imbalance and to better understand the relationship of Europeans and Near Easterners, we report genome-wide data from two [~]26 thousand year old individuals from Dzudzuana Cave in Georgia in the Caucasus from around the beginning of the LGM. Surprisingly, the Dzudzuana population was more closely related to early agriculturalists from western Anatolia [~]8 thousand years ago8 than to the hunter-gatherers of the Caucasus from the same region of western Georgia of [~]13-10 thousand years ago5. Most of the Dzudzuana populations ancestry was deeply related to the post-glacial western European hunter-gatherers of the Villabruna cluster3, but it also had ancestry from a lineage that had separated from the great majority of non-African populations before they separated from each other, proving that such Basal Eurasians6,9 were present in West Eurasia twice as early as previously recorded5,6. We document major population turnover in the Near East after the time of Dzudzuana, showing that the highly differentiated Holocene populations of the region6 were formed by Ancient North Eurasian3,9,10 admixture into the Caucasus and Iran and North African11,12 admixture into the Natufians of the Levant. We finally show that the Dzudzuana population contributed the majority of the ancestry of post-Ice Age people in the Near East, North Africa, and even parts of Europe, thereby becoming the largest single contributor of ancestry of all present-day West Eurasians.

genetics↗