Our ancestors took a 30,000 year “break” in the Arabian Peninsula that changed our genome!
A new study based in particular on genetic criteria shows that during its dispersion outside Africa, modern humans would have taken a 30,000-year “pause” on the Arabian Peninsula. Time to adapt physiologically to face the cold climate of northern lands.
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If it is more or less established that modern man (A wise man) appeared in Africa more than 200,000 years ago, the way it has spread across the world still contains many gray areas. It is commonly believed that this dispersal occurred about 60,000 to 50,000 years ago on the Eurasian continent. This great migratory history towards the north, however, seems to have been interspersed with stops along the way.
A new study published in PNAS indeed reveals that the communities ofA wise man would not have joined Eurasia directly. During their migration, they would have stopped at the level of the peninsulapeninsula Arabic for a long, very long period of more than 30,000 years, before continuing their colonization of the territories located further north. This “pause” would have allowed these human beings to gradually adapt to colder climatic conditions, giving them the ability to survive later in more northern regions. However, these physical adaptations are still visible in our genetic heritage. This is what researchers from theAustralian Center for Ancient DNA from the University of Adelaide (Australia). Most of these changes geneticgenetic would also be associated today with diseases such asobesityobesitythe diabetesdiabetes and cardiovascular disorders.
A story written in our genome
It is interesting to note how the first sequencingsequencing full of genomegenome in the year 2000 paved the way for a phenomenal number of studies and scientific advances, both in the field of medicine and in the history of Humanity. Because the great stages of our past can be read in our GenoaGenoa.
Like all organisms on Earth, human beings have indeed undergone many changes in the face of the constraints imposed by their living environment. This tremendous capacity for adaptation is what would have enabled modern humans to colonize the entire globe, supplanting all other speciesspecies d’hominidshominids.
Certain events of the past thus seem to have notably influenced the human genome by means of a natural selectionnatural selection drastic. However, it is not easy today to find the traces of these changes, the mixing of populations, in particular, tending to erase this genetic signature.
A break in the Arabian Peninsula
However, the scientists managed to identify 57 regions of the genome corresponding to a genetic evolution that was beneficial to ancient human groups. The study thus reveals that a major phase of adaptation occurred before the great dispersal in Eurasia 60,000 to 50,000 years ago. This phase would have lasted no less than 30,000 years. Nicknamed the “Arabian pause”, it is highlighted by genetic, but also archaeological and climatic criteria which suggest that our ancestors stopped in their ascent towards the north in the vicinity of the Arabian Peninsula, the time of adapt to a climateclimate colder. The genetic adaptations gained during this period would thus be linked to the capacity for storing fat, to nerve development, to the physiology of the skin and to the development of tiny fibers (” eyelasheseyelashes ”) in our airways. These changes would have been driven in response to a cold and dry climate prevailing on the Arabian Peninsula between 80,000 and 50,000 years ago.
It is interesting to see that in our modern world, largely modeled by us, these adaptations that were beneficial 50,000 years ago are now sources of disease!
Apart from the fact that these results provide a better understanding of the history of human migrations, the identification of these genetic changes could allow the development of new therapeutic and preventive approaches for current populations.