The most detailed report to date on the genetic history of European humans who lived during the Ice Age. This is the outcome of the work by an international team of scientists that includes two from the University of Siena (Annamaria Ronchitelli and Stefano Ricci) and two from Florence (David Caramelli and Martina Lari). Together they analysed the genetic code of fifty-one individuals living in Europe between 45,000 and 7,000 years ago, before the introduction of agriculture.
The results of this investigation that increased tenfold the sample of ancient DNA belonging to populations of European hunter-gatherers, have just been published in Nature (DOI:10.1038/nature17993).
Three of the fossil specimens came from Grotta Paglicci in Puglia, where Annamaria Ronchitelli from the Department of Physics, Earth and Environmental Sciences in Siena coordinated the research in collaboration with Puglia's Superintendence of Archaeology. The genetic analysis of these finds was performed by the Laboratory of Molecular Anthropology and Paleogenetics of the University of Florence, directed by David Caramelli of the Department of Biology.
The enormous amount of information collected by examining the human remains has made possible to monitor genetic changes happened in over 30,000 years of history and their relationship with cultural transformations. The study has confirmed with greater clarity the decline of Neanderthal DNA found in modern genome.
In particular, in the samples analysed scientists have detected between 3 and 6% of Neanderthal DNA, which, in present-day humans, is reduced to 2% because "evolutionally disadvantageous ".
In addition, the study has made known that one of the lineage to which the first European inhabitants belonged, apparently extinguished itself around 33,000 years ago replaced by a successive lineage, reappeared in some of the samples dating back to the end of Maximum Glacial, around 20,000 years ago.
Another major discovery highlights the emergence, as early as 14,000 years ago, of a new genetic component, currently present in populations of the Near East and probably introduced in Europe from those areas through a migratory flux favoured by the climatic warming. The DNA examined shows also that in the same period there has been a contact with populations from the Far East, which in turn lead to a further transformation of the human landscape.
The study was a collaborative effort by various universities and research institutions worldwide under the supervision of David Reich (Harvard Medical School), Svante Pääbo (Max Planck Institute in Leipzig) and Johannes Krause (University of Tübingen).