April 2021

We are proud to announce the first paper of RESOLUTION team member and Ph.D. student Silvia Cercatillo published in the New Journal of Chemistry.

Exploring different methods of cellulose extraction for 14C dating

Abstract

In this study we aim to identify the optimal cellulose extraction protocol for 14C dating of wood, with a focus on glacial trees. To achieve this, we compare three cellulose extraction methods on the basis of cellulose yield and 14C age. The study is conducted on 12 wood samples of different species, in varying states of preservation with ages covering the full 14C age range. Cellulose is extracted from each sample following three different protocols selected from the literature: ABA-B, BABAB and 2Chlorox. The extracted cellulose was graphitised and dated with the MICADAS (Mini Carbon Dating System) at the ETH AMS laboratory. Although all three methods are considered efficient, the BABAB protocol, despite being a more aggressive procedure, allows the extraction of a sufficient amount of cellulose to be 14C dated and leads to the most reliable results, particularly for very old and background samples (samples with 14C content of zero).

Graphic abstract
Map of sites LGM

Another paper was published and is available online!

"Early Alpine occupation backdates westward human migration in Late Glacial Europe"  Bortolini et al. 2021

Abstract

The end of the Last Glacial Maximum (LGM) in Europe (~16.5 ka ago) set in motion major changes in human culture and population structure. In Southern Europe, Early Epigravettian material culture was replaced by Late Epigravettian art and technology about 18-17 ka ago at the beginning of southern Alpine deglaciation, although available genetic evidence from individuals who lived ~14 ka ago opened up questions on the impact of migrations on this cultural transition only after that date. Here we generate new genomic data from a human mandible uncovered at the Late Epigravettian site of Riparo Tagliente (Veneto, Italy), that we directly dated to 16,980-16,510 cal BP (2σ). This individual, affected by a low-prevalence dental pathology named focal osseous dysplasia, attests that the very emergence of Late Epigravettian material culture in Italy was already associated with migration and genetic replacement of the Gravettian-related ancestry. In doing so, we push back by at least 3,000 years the date of the diffusion in Southern Europe of a genetic component linked to Balkan/Anatolian refugia, previously believed to have spread during the later Bølling/Allerød warming event (~14 ka ago). Our results suggest that demic diffusion from a genetically diverse population may have substantially contributed to cultural changes in LGM and post-LGM Southern Europe, independently from abrupt shifts to warmer and more favorable conditions.

Read the full paper at ScienceDirect; Current Biology; Sequentia; click on the title to read the PDF version;

or read the press release in Italian at Unibo Magazine: "Le migrazioni che hanno cambiato il patrimonio genetico degli europei sono più antiche di quanto pensavamo".

DNA map of Eurasia

A new paper was published!

"Initial Upper Palaeolithic humans in Europe had recent Neanderthal ancestry"

An analysis of nuclear genome sequences from human specimens recovered from Bacho Kiro Cave, reported by Mateja Hajdinjak and colleagues in Nature, sheds light on these individuals' ancestry and their relationships with present-day humans. The oldest three individuals are found to share more genetic variants with present-day populations from East and Central Asia and the Americas than from western Eurasia. These individuals carried between 3% and 3.8% of Neanderthal DNA, and the distribution of Neanderthal genetic material in these genomes indicates that they may have had Neanderthal ancestors as little as six or fewer generations back. The data suggests that mixing between modern humans and Neanderthals may have been more common than previously thought.

Abstract

Modern humans appeared in Europe by at least 45,000 years ago, but the extent of their interactions with Neanderthals, who disappeared by about 40,000 years ago, and their relationship to the broader expansion of modern humans outside Africa are poorly understood. Here we present genome-wide data from three individuals dated to between 45,930 and 42,580 years ago from Bacho Kiro Cave, Bulgaria. They are the earliest Late Pleistocene modern humans known to have been recovered in Europe so far, and were found in association with an Initial Upper Palaeolithic artefact assemblage. Unlike two previously studied individuals of similar ages from Romania and Siberia who did not contribute detectably to later populations, these individuals are more closely related to present-day and ancient populations in East Asia and the Americas than to later west Eurasian populations. This indicates that they belonged to a modern human migration into Europe that was not previously known from the genetic record, and provides evidence that there was at least some continuity between the earliest modern humans in Europe and later people in Eurasia. Moreover, we find that all three individuals had Neanderthal ancestors a few generations back in their family history, confirming that the first European modern humans mixed with Neanderthals and suggesting that such mixing could have been common.

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