The Trail to Modern Humanity

Posted: September 20, 2018 in science
Tags: , , ,

This information was gleaned from the science and tech division of the Daily Mail, as are the artists renditions and graphs you will see in this article.

 

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Hybrid Neanderthal love child is found in a cave in Siberia: Teenage daughter of a Neanderthal mother and a Denisovan father who lived 50,000 years ago reveals how humans’ ape-like cousins frequently interbred!  

A prehistoric 13-year-old girl who lived 50,000 years ago was the love child of two separate species of ancient human ancestor, according to a new DNA analysis of her remains.

A study of a tiny bone fragment found in a cave in Russia shows the teenager had a Neanderthal mother and a Denisovan father, giving fresh insight into how the now-extinct species interacted.

The find suggests that our ape-like cousins mated far more frequently than researchers thought, according to archaeologists.

Neanderthals and Denisovans share a common ancestor with humans and roamed Eurasia as far back as 400,000 years ago having migrated from Africa.

The pair of human-like species then intermingled with modern humans when they arrived on the continent 40,000 years ago, with members of three species sometimes crossbreeding.

This means that tiny amounts of Neanderthal and Denisovan DNA can be found in our genome today! As much as 2% of our DNA was passed on to us from Neanderthals.

Research also shows that two modern genomes, one from Oceana and another from East Asia have distinct Denisovan ancestry.

“Previous studies that Neanderthals and Denisovans must have occasionally had children together,” said study coauthor Viviane Slon of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.

“But I never thought we would be so lucky as to find an actual offspring of the two groups.”

Archaeologists came to their finding after sequencing the DNA of bone found in the Denisova Cave in Siberia’s Altai Mountains.

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The ancient individual is only represented by a single fragment so small that researchers call it a ‘bone needle’.

‘The fragment is part of a long bone, and we can estimate that this individual was at least 13 years old,” said Dr. Bence Viola, an archaeologist at the University of Toronto who was not involved in the study.

After sequencing the genome of the young girl, scientists found she was the child of a Neanderthal mother and Denisovan father – putting her among the first specimens to show direct evidence the species mixed.

“An interesting aspect of this genome is that it allows us to learn things about two populations – the Neanderthals from the mother’s side, and the Denisovans from the father’s side,” said co-author Dr. Fabrizio Mafessoni.

Thousands of ancient hominin bones were uncovered in the Denisova Cave in 2012, including the 120,000-year-old toe bone of a Neanderthal and the first ever evidence of a Denisovan – the phalanx of a child who lived between 30,000 and 40,000 years ago.

It is commonly believed that a common ancestor of the two species migrated from Africa to Eurasia between 400,000 and 300,000 years ago and then split.

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The traditional “Out of Africa” model suggests that modern humans evolved in Africa and then left in a single wave around 60,000 years ago.

The model often holds once modern humans left the continent, a brief period of interbreeding with Neanderthals occurred.

This explains why individuals of European and Asian heritage today still have ancient human DNA.

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There are many theories as to what drove the downfall of the Neanderthals.

Experts have suggested that early humans may have carried tropical diseases with them from Africa that wiped out their ape-like cousins.

Others claim that plummeting temperatures due to climate change wiped out the Neanderthals.

The predominant theory is that early humans killed off the Neanderthal through competition for food and habitat.

How the story is changing in light of new research

Recent findings suggest that the ‘Out of Africa’ theory does not tell the full story of our ancestors.

Instead, multiple, smaller movements of humans out of Africa beginning 120,000 years ago were then followed by a major migration 60,000 years ago.

Most of our DNA is made up of this latter group, but the earlier migrations, also known as “dispersals”, are still evident.

This explains recent studies of early human remains which have been found in the far reaches of Asia dating back further than 60,000 years.

For example, H. sapiens remains have been found at multiple sites in southern and central China that have been dated to between 70,000 and 120,000 years ago.

Other recent finds show that modern humans reached Southeast Asia and Australia prior to 60,000 years ago.

Based on these studies, humans could not have come in a single wave from Africa around this time, studies have found.

Instead, the origin of man suggests that modern humans developed in multiple regions around the world.

The theory claims that groups of pre-human ancestors made their way out of Africa and spread across parts of Europe and the Middle East.

(I support the above hypothesis, as I have done other studies that support the multiple group theory! Opinion by John love)

From here the species developed into modern humans in several places at once.

The argument is by a new analysis of a 260,000-year-old skull found in Dali County in China’s Shaanxi Province.

The skull suggests that early humans migrated to Asia, where they evolved modern human traits and then moved back to Africa.

 

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