DNA From Ancient Site in Spain Reshapes Human Family Tree

400,000-year-old keleton from Spain, from news.nationalgeographic.com
400,000-year-old skeleton from Spain, from news.nationalgeographic.com

Six weeks ago I suggested that 2013 was already the breakthrough year for molecular anthropology, but 2013 is ending with yet another highlight. Yesterday, Nature published a stop-you-in-your tracks piece that scrambles the scientific picture of our ancient relatives.  The world-leading Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany successfully sequenced the mitochondrial genome of a 400,000 year-old ancient human from Spain. The DNA suggests the specimen was maternally related to Denisovans, rather than Neanderthals, which leaves anthropologists puzzled and may be shifting branches around in the human family tree.

Denisovan tooth
Denisovan tooth, from www.genographic.com

The term Denisovan, distinct to both modern humans and Neanderthals, was coined just three years ago based on some limited tooth morphology, but predominantly on the distinct DNA sequenced from a 41,000 year-old toe bone found in central Asia. Since then, anthropologists have theorized that Denisovans were contemporary Asian “cousins” to Neanderthals found in Europe and the Middle East, and to modern humans who were already living throughout Africa and were venturing out of the continent for the first time 10,000 years earlier.

Wilma the Neanderthal, by Becky Hale.
Wilma the Neanderthal, by Becky Hale.

That was the accepted story guiding anthropologists just last month.  Now the story has changed and we are scrambling to come up with a new narrative. Is this a different species ancestral to Denisovan, but not Neanderthals? Were there two movements out of Africa before the third and final migration that Homo sapiens took in the last 50,000 years? How many different species of hominids lived in Europe, Africa and Asia in the Pleistocene? And since these beings surely interbred, can we even call them separate species? When the dust settles, a new story of human ancestry will have surely emerged. What do you think was happening back then?

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Dr. Miguel Vilar is the Science Manager for National Geographic's Genographic Project. Miguel is also a molecular anthropologist and a science writer. His fieldwork has taken him to remote places throughout the South Pacific, East Africa, Mesoamerica, and the Caribbean. In the laboratory he researches the modern genetic diversity of human populations from Melanesia, Micronesia, North and Central America, and the Caribbean. Miguel has published in several anthropology and genetics journals, as well as popular science magazines.