VOA Special English
New Study Provides Evidence of Mysterious Human Species

    2020/2/23

    A new study suggests that a mysterious human species mated with our own species tens of thousands of years ago in Africa.

    Researchers say the study provides evidence that present-day West Africans can link about 2 to 19 percent of their genetic ancestry to an extinct human species. The study describes the species as a “ghost population.”

    Scientists involved in the research estimated that mating between the two species happened about 43,000 years ago.

    In this file photo, Yinka Sotomi stands atop Oluma Rock, a spiritual site for the Yoruba tribe, overlooking the city of Abeokuta in southern Nigeria, April 16, 2007. (REUTERS/Finbarr O'Reilly)
    In this file photo, Yinka Sotomi stands atop Oluma Rock, a spiritual site for the Yoruba tribe, overlooking the city of Abeokuta in southern Nigeria, April 16, 2007. (REUTERS/Finbarr O'Reilly)

    Homo sapiens – the species of human that exists today - first appeared more than 300,000 years ago in Africa. The species later spread worldwide.

    Earlier genetic research has shown that our species mated with two early human species, the Neanderthals and the Denisovans. The species have been extinct for thousands of years, but modern human populations outside Africa still carry DNA from both.

    Scientists have discovered many fossil records relating to the Neanderthals and a few from the Denisovans. So far, though, very little is known about the newly identified “ghost population.”

    Sriram Sankararaman is a human genetics and computer science professor at the University of California, Los Angeles. He led the study, which was recently published in Science Advances.

    Sankararaman told the Reuters news agency that “not much” is known about this mysterious species. “We don’t know where this population might have lived, whether it corresponds to known fossils, and what its ultimate fate was,” he added.

    Sankararaman said the extinct species likely split off about 650,000 years ago from the evolutionary line that led to Homo sapiens.

    The study used genetic data from hundreds of West Africans, including the Yoruba people of Nigeria and Benin and the Mende people of Sierra Leone. The researchers compared the data with DNA information from the Neanderthals and Denisovans.

    Scientists say they uncovered DNA material in the West Africans that can best be explained by ancestral interbreeding with an unknown member of the human family tree.

    Sankararaman said it is no longer necessary to consider only DNA from fossils of early human species to confirm that humans intermixed with them. “We can now see that such events took place by looking at our own DNA itself.”

    He added that the discovery “opens a new path in understanding the complexity of human evolutionary history in Africa, where the picture hasn’t been as clear.”

    I’m Bryan Lynn.

    Reuters news agency reported on this story. Bryan Lynn adapted the report for VOA Learning English. Ashley Thompson was the editor.

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    Words in This Story

    extinct adj. no longer living or existing

    ghost n. the spirit of a dead person that can appear to living people

    fossiln. part of an animal or plant from the past that has been preserved in rock

    correspond v. to be the same or similar

    fate n. what happens to a person, especially when it is something bad

    ultimate adj. final or most important

    evolutionary adj. gradual process of change and development