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Scientists Have Found New Evidence to Show How Early Humans Migrated Into Europe
Aug. 12, 2013 — Humans originated in Africa. But what route did they take as they began to disperse around the world 60,000 years ago?
The article in PLoS ONE provides new evidence to indicate that early humans migrated into Europe after the Last Glacial Maximum but before Neolithic times, giving us a clearer picture of how early humans were developing at this time. Professor Richards spent ten years as a researcher at Oxford University before first coming to the University of Huddersfield for a lecturing post in 2000. He then moved to Leeds, where he was awarded his professorship, before returning to Huddersfield, where he is currently equipping archaeogenetics research facilities. He is joined by his colleagues Dr Maria Pala, Dr Paul Brotherton and Dr Martin Carr.
One laboratory is being set up for the main molecular biology work and a separate lab built for the analysis of ancient DNA. There must be no risk of the evidence being cross-contaminated. "It's like forensics but even more so. It has to be in another building, segregated from the rest of the work we do here," said Professor Richards.
quote: The current human mitochondrial (mtDNA) phylogeny does not equally represent all human populations but is biased in favour of representatives originally from north and central Europe. This especially affects the phylogeny of some uncommon West Eurasian haplogroups, including I and W, whose southern European and Near Eastern components are very poorly represented, suggesting that extensive hidden phylogenetic substructure remains to be uncovered. This study expanded and re-analysed the available datasets of I and W complete mtDNA genomes, reaching a comprehensive 419 mitogenomes, and searched for precise correlations between the ages and geographical distributions of their numerous newly identified subclades with events of human dispersal which contributed to the genetic formation of modern Europeans. Our results showed that haplogroups I (within N1a1b) and W originated in the Near East during the Last Glacial Maximum or pre-warming period (the period of gradual warming between the end of the LGM, ~19 ky ago, and the beginning of the first main warming phase, ~15 ky ago) and, like the much more common haplogroups J and T, may have been involved in Late Glacial expansions starting from the Near East. Thus our data contribute to a better definition of the Late and postglacial re-peopling of Europe, providing further evidence for the scenario that major population expansions started after the Last Glacial Maximum but before Neolithic times, but also evidencing traces of diffusion events in several I and W subclades dating to the European Neolithic and restricted to Europe.
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Mitogenomes from Two Uncommon Haplogroups Mark Late Glacial/Postglacial Expansions from the Near East and Neolithic Dispersals within Europe Anna Olivieri mail, Maria Pala,Francesca Gandini, Baharak Hooshiar Kashani,Ugo A. Perego,Scott R. Woodward,Viola Grugni, Vincenza Battaglia,Ornella Semino, Alessandro Achilli,Martin B. Richards,Antonio Torroni
Discussion excerpt
The direct comparison of ancient and modern DNA samples, allowing a diachronic view of human history, can be an important test of inferences based on data from extant populations. Having improved the resolution of the N1a1b and W phylogenies, we were then able to re-evaluate the published I and W control-region haplotypes from ancient specimen (Table 3) in the context of the modern variation of I and W mitogenomes (Figure S1 and Figure S2). Since only information relative to the HVS-I is available, most of the ancient I and W mtDNAs bear basal and/or common haplotypes, which could not be further classified within any subclade. However, a few informative cases were identified. A Spanish middle Neolithic sample [40] bearing the haplogroup I control-region motif 16264-16270-16311-16319-16362 (from the root of I) (Table 3) can now be classified within I1c1. The identification of this sample has already been interpreted as indicating genetic continuity in the Iberian Peninsula since the Neolithic period and (more contentiously, given the paucity of Mesolithic evidence from Iberia) that the diffusion of agriculture followed a demic model in the Mediterranean area [40]. We found that the same I1c1 haplotype is shared by five mitogenomes in our phylogeny (#60-64 in Figure S1), of which four are of unknown geographic/ethnic origin but one (sample #64, sequenced in the present study) was of North Italian origin. This result provides a further confirmation of our findings, based on the analysis of haplogroup I phylogeny, that (i) subclade I1c1 was likely a marker of Neolithic dispersal in Europe (rather than, for example, having been brought from the Near East much more recently by the ancestors of Ashkenazi Jews, some of whom carry this lineage [67], [68]) and (ii) the distribution and age might support a demic model of Neolithic diffusion in the Mediterranean area. Similarly, a probable member of haplogroup W3 in the same Spanish Neolithic sample [40], sharing the haplotype 16292-16295-16304 (against the root of N) with a mitogenome from Azerbaijan (sample #127) in our phylogeny), may point to Neolithic dispersal from the Near East into Europe.
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