During the last glacial maximum, much of Europe was depopulated and re-settled, about 15,000 years ago. Northern Europe was largely covered by ice, the southern boundary of the ice sheets passing through Germany and Poland. This ice extended northward to cover Svalbard and Franz Josef Land and northeastward to occupy the Barents Sea, the Kara Sea and Novaya Zemlya, ending at the Taymyr Peninsula.
Permafrost covered Europe south of the ice sheet down to present-day Szeged in Southern Hungary. Ice covered the whole of Iceland and almost all of the British Isles but southern England. Britain was no more than a peninsula of Europe, its north capped in ice, and its south a polar desert.
The world was gripped in an Ice Age around 19 000 years ago, leaving large tracts cold, dry and inhospitable. Much of northern Europe was covered by ice, northern areas of what is now the United Kingdom were covered in ice, while its south was little more than a polar desert. The Ice Age, however, eventually came to an end and as the ice retreated, Europe once again began to be populated by human beings. New research drawing in expertise from the Czech Republic, Estonia, Italy, Russia and the United Kingdom is giving us rare insight into how Europe became repopulated as the Ice Age ended. The findings were published in the American Journal of Human Genetics.
'The end of the Last Glacial Maximum allowed people to recolonise the parts of Europe that had been deserted and this expansion allowed increase of human populations,' said lead author Sardinian-born Dr Maria Pala, who began research into the topic while at the University of Pavia in Italy before moving to the United Kingdom.
Led by Dr Pala, who is currently based at the University of Huddersfield, United Kingdom, and her team showed how the Near East was a major source of replenishment when huge areas of European territory became habitable again, up to 19 000 years ago.
The Last Glacial Maximum, or Ice Age as it is more commonly referred as, lasted for around 7 000 years. When it began some 26 000 years ago, it was thought that there were two principal safe havens for humans. They were thought to exist in a "Franco-Cantabrian" area which roughly coincides with northern Spain/southern France, and a 'Periglacial province' on the plains in the Ukraine.
By analysing large quantities of mitochondrial deoxyribonucleic acid (DNA) from Europeans who belong to two major lineages - who share a common genetic ancestor - named J and T, the researchers filled in many of the gaps that have existed and created a more complete picture of early Europeans. What is known is that these haplogroups (groups sharing similar DNA traits such as J and T) originated in the Middle East, and up until now it was thought that they migrated to Europe in the Neolithic age, approximately 9 000 years ago.
However, the team provided evidence that shows humans belonging to the J and T haplogroups actually migrated to Europe much earlier than was previously thought, beginning as soon as the Ice Age started to end.
Aside from the purely scientific challenges and discoveries, Dr Pala believes that archaeo-genetics has important lessons to teach humanity: 'It (archaeo-genetics) helps us to reevaluate the perception of our identity. We are highly focused on identifying ourselves as Italians, British or whatever, but by analysing DNA we discover that originally, not such a long time ago, we came from a common source.'
Reference: Pala, M., et al. 'Mitochondrial DNA Signals of Late Glacial Recolonization of Europe from Near Eastern Refugia'. The American Journal of Human Genetics, 2012; 90 (5): 915 doi: 10.1016/j.ajhg.2012.04.003
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But haplogroups J and T are relatively rare in Europe. The dominant haplogroups in Europe are I and R--with some[minimal] J and E.
And note that in areas where conditions are Artic humans and animals have lived there for millenia. Inuits(Eskimos), polar bears, Artic foxes, seals, have all survived in extremely cold conditions and have adapted to such--Polar bears, Artic foxes, etc.--provided there were food sources.
Posts: 5492 | Registered: Nov 2004
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quote:Originally posted by lamin: But haplogroups J and T are relatively rare in Europe. The dominant haplogroups in Europe are I and R--with some[minimal] J and E.
And note that in areas where conditions are Artic humans and animals have lived there for millenia. Inuits(Eskimos), polar bears, Artic foxes, seals, have all survived in extremely cold conditions and have adapted to such--Polar bears, Artic foxes, etc.--provided there were food sources.
better eleboration in the source article:
excerpts:
Mitochondrial DNA Signals of Late Glacial Recolonization of Europe from Near Eastern Refugia
Maria Pala1 Human populations, along with those of many other species, are thought to have contracted into a number of refuge areas at the height of the last Ice Age. European populations are believed to be, to a large extent, the descendants of the inhabitants of these refugia, and some extant mtDNA lineages can be traced to refugia in Franco-Cantabria (haplogroups H1, H3, V, and U5b1), the Italian Peninsula (U5b3), and the East European Plain (U4 and U5a). Parts of the Near East, such as the Levant, were also continuously inhabited throughout the Last Glacial Maximum, but unlike western and eastern Europe, no archaeological or genetic evidence for Late Glacial expansions into Europe from the Near East has hitherto been discovered. Here we report, on the basis of an enlarged whole-genome mitochondrial database, that a substantial, perhaps predominant, signal from mitochondrial haplogroups J and T, previously thought to have spread primarily from the Near East into Europe with the Neolithic population, may in fact reflect dispersals during the Late Glacial period, ∼19–12 thousand years (ka) ago.
Haplogroup J makes up almost 9% of mtDNAs in Europe and ∼13% in the Near East. The geographic distribution of its subclades supports the view that haplogroup J initially diversified in the Near East. A single lineage from the North Caucasus, defined only by the recurrent HVS-I transition at np 16193, branches immediately before J1d in our tree, and may represent a paraphyletic lineage within J1. If so, it would be the only lineage found not to fall within one of the five major subclades of haplogroup J; possible related lineages in the control-region database are found in Turkey, close to the likely source area for J1.
Haplogroup T makes up almost 10% of mtDNAs in Europe and ∼8% in the Near East. Like J1 and J2, T1 and T2 most likely originated in the Near East, and both date to ∼21 ka ago, although the origin of T2 is the least clear and an ancient presence in Europe is possible. T1 represents ∼2% of overall genetic variability in western Europe and ∼3% in eastern Europe and the Near East, whereas T2 reaches ∼8% in western Europe and ∼5% in the Near East.
From the genetic point of view, it has been suggested that the second principal component of classical marker variation in Europe may have been formed by the Late Glacial expansion,12 and there has been evidence from mtDNA for human expansions from the Franco-Cantabrian refugium; namely, signatures in haplogroups V,12 and 13 H1, H3,14 and 15 H5,16 and U5b1b17 and 18 as well as in haplogroup U5b3, indicating dispersal from the Italian Peninsula,19 and in U4 and U5a, indicating expansion from the East European Plain.20 and 21 As for the male-specific region of the Y chromosome (MSY), previous studies suggested that the European frequency clines associated with R1a-M17 and R1b-M173 (xM17) (now called R1b-M269) might have been due to population expansions from Ukrainian and Franco-Cantabrian refugia, respectively.22, 23 and 24 Although a more complex scenario is emerging from the progressive improvement of the Y chromosome phylogeny,25, 26, 27, 28 and 29 signs of post-LGM re-expansions from eastern European, Iberian, and southern Balkan refugia are suggested by the distribution of some R (R1a-M458, R1b-M412)25 and 27 and I (I-M423)30 subclades, respectively. By contrast, the majority of mtDNA haplogroups J and T131 and 32 and Y chromosome haplogroup J,22 along with G2a and E1b1b1a1b (on the basis of ancient-DNA studies),33, 34 and 35 have been proposed as candidates for markers of the Neolithic expansion into Europe from its origin in the Fertile Crescent of the Near East.16
There is, however, another potential refugium for European genetic variation, which is not present in Dolukhanov's model and does not appear to have been considered seriously by either archaeologists or geneticists. Studies have established that populations persisted throughout the last glaciation in parts of the Near East, such as the Levant36 and coastal southern Turkey, and that genetic variation in the Near East encompasses much of the diversity now found in Europe. It is possible that the Near East has been overlooked as a refugium for Europeans because of the emphasis throughout much of the twentieth century on its role as a reservoir for subsequent Neolithic dispersals, which first reached southeastern Europe ∼9 ka ago. For example, the first principal component of variation in classical markers in western Eurasia has often been regarded as evidence for a demic diffusion of people into Europe during the Neolithic period,37 and various mtDNA and MSY lineages thought to originate in the Near East have been proposed as markers of the Neolithic dispersal. Therefore, to investigate the possibility of Late Glacial dispersals into Europe from the Near East ∼19–12 ka ago, we decided to reevaluate the roles of mtDNA haplogroups J and T.
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When I wrote haplogroups I and R being predominant in Europe I meant Y(male) haplogroups. Again the Y haplogroups of E and J exist in Europe but are relatively not significant.
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quote:Originally posted by lamin: But haplogroups J and T are relatively rare in Europe. The dominant haplogroups in Europe are I and R--with some[minimal] J and E.
And note that in areas where conditions are Artic humans and animals have lived there for millenia. Inuits(Eskimos), polar bears, Artic foxes, seals, have all survived in extremely cold conditions and have adapted to such--Polar bears, Artic foxes, etc.--provided there were food sources.
better eleboration in the source article:
excerpts:
Mitochondrial DNA Signals of Late Glacial Recolonization of Europe from Near Eastern Refugia
blah blah blah... of mtDNA haplogroups J and T.
LOL!
Queen of cut and paste without comprehension
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