The History Room
Artificial Intelligence Study of Human Genome Finds Unknown Human Ancestor
A neat article that goes into ancient human history. Some good graphics at the link.
Read the entire article at the link.A recent study used machine learning technology to analyze eight leading models of human origins and evolution, and the program identified evidence in the human genome of a “ghost population” of human ancestors. The analysis suggests that a previously unknown and long-extinct group of hominins interbred with Homo sapiens in Asia and Oceania somewhere along the long, winding road of human evolutionary history, leaving behind only fragmented traces in modern human DNA.
The study, published in Nature Communications, is one of the first examples of how machine learning can help reveal clues to our own origins. By poring through vast amounts of genomic data left behind in fossilized bones and comparing it with DNA in modern humans, scientists can begin to fill in some of the gaps of our species’ evolutionary history.
In this case, the results seem to match paleoanthropology theories that were developed from studying human ancestor fossils found in the ground. The new data suggest that the mysterious hominin was likely descended from an admixture of Neanderthals and Denisovans (who were only identified as a unique species on the human family tree in 2010). Such a species in our evolutionary past would look a lot like the fossil of a 90,000-year-old teenage girl from Siberia's Denisova cave. Her remains were described last summer as the only known example of a first-generation hybrid between the two species, with a Neanderthal mother and a Denisovan father.
“It's exactly the kind of individual we expect to find at the origin of this population, however this should not be just a single individual but a whole population,” says study co-author Jaume Bertranpetit, an evolutionary biologist at Barcelona's Pompeu Fabra University.
The ability of early humans to adjust to changing conditions ultimately enabled the earliest species of Homo to vary, survive and begin spreading from Africa to Eurasia 1.85 million years ago. (Image courtesy of Antón, Potts and Aiello (2014), Science 345(6192))Previous human genome studies have revealed that after modern humans left Africa, perhaps 180,000 years ago, they subsequently interbred with species like Neanderthals and Denisovans, who coexisted with early modern humans before going extinct. But redrawing our family tree to include these divergent branches has been difficult. Evidence for “ghost” species can be sparse, and many competing theories exist to explain when, where, and how often Homo sapiens might have interbred with other species.
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