The oldest African genome rewrites history of human evolution

Oldest genome rewrites history of Africa human evolution


  • posted on Science oldest sequencing the genome of the African continent.
  • The flows migration from Europe to the Horn of Africa had a decisive influence on the genetic diversity of the continent.

Africa is the cradle of humanity. The place that allows us to understand the roots of the human species. So far, however, no study had managed to sequence the genome ancestral fossils obtained from the continent. The reason was the instability of the DNA molecule itself, which was affected by the temperature and humidity conditions. New research, published in Science , has managed to analyze first the oldest genome found in the continent, rewriting the history of evolution human.

The skeleton found in 2012 by John and Kathryn Arthur in the Cave Mota put on Ethiopia researchers track. The excavation, located at an altitude of 1963 meters in the southwest of the country, had good conditions of temperature and humidity. The microclimate of the cave allowed the conservation of DNA during 4500 years, estimated the remains of this adult male as genomic analysis, might have brown eyes and dark skin age.


How migration affected genetic diversity

The physical features of the individual are not the most striking feature of the results of the sequencing genomics. As published in the journal Science , the analysis of ancient DNA has allowed more accurately trace the history of human evolution. Migration from the Middle East, particularly from the regions of Anatolia and Mesopotamia, may have had a greater impact than previously thought. The genome of the Mota Cave of Ethiopia is the oldest I found in Africa

The lack of genomes as old as the Cave Mota made the scientists had to settle for the study of contemporary populations to include the “gene flow “it had happened in Africa . Fortunately, research published today helps us to reconstruct in detail the evolution of our species. The discovery of these fossils allowed the extraction and DNA sequencing of the petrous temporal bone of the skull. Comparing 250,000 base pairs analyzed 40 European and 81 African populations, the researchers saw that the ancestor of Mota was more related to the ethnicity of Ari.

The comparative study showed that genome Mota lacked between 4 and 7% of regions who were both in the group of Ari and the rest of African populations evaluated. What happened to those portions of DNA? According to the results presented, the genetic sequences were more similar to those presented Neolithic farmers who had colonized the European continent 4,000 years before.

evolution

Cave Mota Ethiopia, first excavated by Kathryn and John Arthur.

The discovery of Africa’s oldest genome has allowed therefore draw the important influence of the migration on the genetic diversity of the continent, and therefore own history of human evolution. The data also suggest that these early farmers Ethiopians who returned to these areas could contribute significantly to the changes related to food production in the Horn of Africa.

As noted by Andrea Manica , Department of Zoology, University of Cambridge, “the waves of migration to this region of the African continent could have meant up to 30% of the population living there.” The researcher wonders what would those people to return back to the Horn of Africa. Although this issue has not been resolved, the fact is that the analysis of a single ancestral genome have opened a new window on the past, delving into the history of human evolution.

At the moment, scientists University of Cambridge have ruled that migratory flows were due to some sort of climate change. The scenarios focus on transfomaciones occurred in agricultural production, since migration coincided in time with the arrival of crops such as barley and wheat to the region. DNA sequencing shows importance of migration on genetic diversity

Anyway, the ancestral genome sequencing This is an important milestone in biology research. As Sara points Monzon, Bioinformatics Unit of the Institute of Health Carlos III, “the coverage achieved in the study [12.5x] of samples is high considering the origin of them.”

In a common analysis exome (the coding region of the genome) with sequence coverage is typically 100x and 20x in contemporary genomes. “The technical reliability of the work, considering the age of the DNA, is quite an achievement,” said the scientific . A success that also allows us to hear more about our own origins, and look back into the past of the human species.


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The oldest African genome rewrites history of human evolution
Source: english  
October 8, 2015


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