Thursday, August 11, 2022

DNA analysis revealed the identity of mystery fossils

DNA from the ancient population in Southern China suggests Native Americans’ East Asian roots.

Three decades ago, a group of archaeologists in China discovered a large set of bones in the Maludong, or Red Deer Cave, in southern China’s Yunnan Province. The fossils were identified by carbon dating as being from the Late Pleistocene, roughly 14,000 years ago- a time when modern humans had migrated to many parts of the world.

Archaeologists also recovered a hominin skull cap from the cave. That skull cap exhibits the characteristics of both modern humans and archaic humans. For example, the shape of the skull resembled that of Neanderthals, and its brain appeared smaller than that of modern humans. As a result, some anthropologists had thought the skull probably belonged to an unknown archaic human species that lived until fairly recently or to a hybrid population of archaic and modern humans.

In 2018, in collaboration with Xueping Ji, an archaeologist at Yunnan Institute of Cultural Relics and Archaeology, Bing Su at Kunming Institute of Zoology, Chinese Academy of Sciences, and his colleagues successfully extracted ancient DNA from the skull.

Genomic analysis reveals that the extinct maternal lineage of a group of modern humans, whose living descendants are now found in East Asia, the Indo-Chinese peninsula, and Southeast Asian islands, is where the hominin originated.

Now, for the first time, by sequencing the genome of ancient human fossils, researchers found that the mystery fossils belonged to an extinct maternal branch of modern humans that might have contributed to the origin of Native Americans.

The lateral view of the skull unearthed from Red Dear Cave
The lateral view of the skull unearthed from Red Dear Cave. Credit: Xueping Ji

Su said, “The finding also shows that during the Late Pleistocene, hominins living in southern East Asia had rich genetic and morphologic diversity, the degree of which is greater than that in northern East Asia during the same period. It suggests that early humans who first arrived in eastern Asia initially settled in the south before some moved to the north.”

“It’s an important piece of evidence for understanding early human migration.”

Researchers are further planning to sequence more ancient human DNA by using fossils from southern East Asia, especially ones that predated the Red Deer Cave people.

Su said“Such data will not only help us paint a complete picture of how our ancestors migrate but also contain important information about how humans change their physical appearance by adapting to local environments over time, such as the variations in skin color in response to changes in sunlight exposure.”

Journal Reference:

  1. Xiaoming Zhang, Xueping Ji, et al. A Late Pleistocene human genome from Southwest China. July 14, 2022. Current Biology. DOI: 10.1016/j.cub.2022.06.016

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