Tuesday, May 26, 2020

French Ancient DNA

A major French ancient DNA study reproduces the paradigm also found in Ireland of Mesolithic, Neolithic and Bronze Age waves of migration producing most of the currently population genetic landscape of France. As this press release explains:
A team led by scientists from the Institut Jacques Monod (CNRS/Université de Paris) have shown that French prehistory was punctuated by two waves of migration: the first during the Neolithic period, about 6,300 years ago, the second during the Bronze Age, about 4,200 years ago. This study, published in PNAS on May 25, which looked at the genomes of 243 ancient individuals over 7,000 years, demonstrates how admixture between native hunter-gatherers and the first Anatolian Neolithic migrants, who brought with them a lifestyle based on agriculture, persists to this day in the genomes of French people. Admixture of the Neolithic populations with those from the Pontic steppes, who arrived 4,200 years ago in what is now France, also left a lasting imprint, with the Y chromosome of the majority of French men still bearing the signature of men from the steppes.
The paper and its abstract are as follows:
Using genomic data as well as paternal and maternal lineages from more than 200 individuals, including 58 low-coverage ancient genomes, we show the population structure from the Mesolithic to the Iron Age in France and trace the changing frequency of genotypes associated with phenotypic traits. Importantly, we also report the late persistence of Magdalenian-associated ancestry in hunter-gatherer populations, showing the presence of this ancestry beyond the Iberian Peninsula in the Late Paleolithic. This study complements the genomic history of western Europe for this broad period by supplying a large genetic transect of three regions of France. 
Genomic studies conducted on ancient individuals across Europe have revealed how migrations have contributed to its present genetic landscape, but the territory of present-day France has yet to be connected to the broader European picture. We generated a large dataset comprising the complete mitochondrial genomes, Y-chromosome markers, and genotypes of a number of nuclear loci of interest of 243 individuals sampled across present-day France over a period spanning 7,000 y, complemented with a partially overlapping dataset of 58 low-coverage genomes. This panel provides a high-resolution transect of the dynamics of maternal and paternal lineages in France as well as of autosomal genotypes. Parental lineages and genomic data both revealed demographic patterns in France for the Neolithic and Bronze Age transitions consistent with neighboring regions, first with a migration wave of Anatolian farmers followed by varying degrees of admixture with autochthonous hunter-gatherers, and then substantial gene flow from individuals deriving part of their ancestry from the Pontic steppe at the onset of the Bronze Age. Our data have also highlighted the persistence of Magdalenian-associated ancestry in hunter-gatherer populations outside of Spain and thus provide arguments for an expansion of these populations at the end of the Paleolithic Period more northerly than what has been described so far. Finally, no major demographic changes were detected during the transition between the Bronze and Iron Ages.

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