August 12, 2013
Genetic Evidence Shows How Early Humans Migrated From Africa To Europe
Brett Smith for redOrbit.com - Your Universe Online
According to a new DNA analysis from an international team of researchers, human expansion most likely occurred after the Last Glacial Maximum, between 26,500 and 19,000 years ago, and the Neolithic Era, approximately 12,000 years ago.
The researchers reached their conclusion by expanding and re-analyzing the available datasets of mitochondrial DNA, or mtDNA, in search of specific signifying markers.
“It seems likely that Late Glacial and postglacial improvements in climate were fundamental to the dispersal of numerous other mtDNA lineages not only in the Near East and Europe, but also in Africa, Asia, the Pacific and the Americas and even some lineages previously thought to be markers for Neolithic expansions have now been recognized as signaling Late Palaeolithic and/or Mesolithic diffusion events,” the team wrote in a report recently published in the open access journal PLOS ONE.
The study used genetic data “from almost 10,000 available subjects of various geographic origins” to construct a series of models and trees depicting the geographic distribution of various mtDNA signatures. The team reported significant evidence suggesting the timing for a major human exodus out of Africa, into the Caucasus and then to both the Near East and Europe.
“This represents a significant step forward in the century-long debate concerning the relative genetic contribution of Palaeolithic versus Neolithic to the current gene pool of modern Europeans,” the team wrote.
The researchers said the next stage of their research should investigate what happened after major migratory waves came out of Africa.
“Now, a still unresolved fundamental question in understanding the genetic makeup of modern Europeans is what exactly happened in the time span of several thousands of years between the Late Palaeolithic/Mesolithic expansions and the arrival of agriculture in the different parts of Europe,” they wrote.
Based on genetic evidence, the scientists speculated that farther human expansions into Europe were probably linked to the proliferation of agriculture.
“With the advent of reliable ancient DNA studies, attention is starting to focus on subsequent events in European prehistory,” they wrote.
In London, archeologists have just uncovered new evidence of activities that occurred after the waves of migration out of Africa, during Neolithic times. The scientists, who were working at a railway construction site, announced that they had found evidence of an ancient tool factory being run by humans on the side of the River Thames in England some 9,000 years ago.
Archeologists said they were able to find 150 pieces of flint that were intended to be used as blades, among other things. Ancient Londoners were probably using the site to test and prepare river stones for making flint tools, the scientists said.
“This unique find reveals evidence of humans returning to Britain and in particular the Thames after a long absence during the Ice Age,” Jay Carve, a lead archaeologist at the Crossrail site in the London borough of Newham, told a local reporter.
“It is one of a handful of archaeology sites uncovered that confirms humans lived along the Thames at this time,” he added.