DNA from fossils unearthed in southern China dating back 14,000 years suggests Native Americans have East Asian roots
- Fossils found in China indicate that Native Americans may have had genetic roots in East Asia
- The data will help us understand “how people change their physical appearance as they adapt to local environments over time,” says study co-author Bing Su
DNA from ancient fossils in southern China has shown that Native Americans may have roots in East Asia.
Scientists compared the genetic information of late Pleistocene fossils to that of humans worldwide.
They found that the bones belonged to an individual closely associated with East Asian Native American ancestry.
Archaeologists had successfully sequenced the genome of the fossils.
Scroll down for videos
Researchers have for the first time successfully sequenced the genome of late Pleistocene fossils. Pictured above is a side view of the skull excavated from Red Deer Cave
“The ancient DNA technique is a really powerful tool,” says Bing Su, a study co-author who works at the Chinese Academy of Sciences.
“It tells us quite clearly that the people in Red Deer Cave, despite their unusual morphological features, were modern humans and not archaic species like Neanderthals or Denisovans.”
They suggested that some of the Southeast Asian peoples traveled north through Japan along the coast of present-day China, eventually reaching Siberia.
“It shows us quite clearly that despite their unusual morphological features, the people in Red Deer Cave were modern humans and not archaic species like Neanderthals or Denisovans,” says Bing Su, co-author of the study. Shown is the reproduced portrait of the Red Deer Cave People or Mengziren
It is believed that they then crossed the Bering Strait between Asia and North America to be the first people to arrive in the New World.
The work leading to these findings began more than thirty years ago.
At that time, a group of archaeologists in China discovered a large set of bones in Maludong, or Deer Cave, in southern China’s Yunnan Province.
Archaeologists used carbon dating – which uses the relative proportions of the carbon isotopes carbon-12 and carbon-14 to determine the age of organic matter – to show the fossils dated to the late Pleistocene, around 14,000 years ago.
The discovery dates back to work that began several decades ago when archaeologists found a large set of bones in Maludong, or Red Deer Cave pictured above
This was a time when modern humans had migrated to many parts of the world.
Researchers recovered a hominin skullcap from the cave that showed features of both modern and archaic humans.
For example, the shape of the skull resembled that of Neanderthals, and their brains appeared to be smaller than modern humans.
As a result, some anthropologists had assumed the skull likely belonged to an unknown archaic human species that lived until recently, or to a hybrid population of archaic and modern humans.
The find adds to our understanding of the rich genetic diversity of hominins that lived in Southeast Asia at the time.
Su says this suggests that early humans, who first arrived in East Asia, first settled in the south before some of them migrated north.
“This is important evidence for understanding early human migration,” he explains.
“Such data will not only help us paint a more complete picture of how our ancestors migrated, but they also contain important information about how humans change their physical appearance by adapting to local environments over time, such as for example, the variations in skin color in response to changes in solar radiation,” says Su.
The team’s findings were published July 14 in the journal Current Biology.
DNA: A COMPLEX CHEMISTRY THAT CARRIES GENETIC INFORMATION IN ALMOST ALL ORGANISMS
DNA, or deoxyribonucleic acid, is a complex chemical found in almost all organisms that carries genetic information.
It is found in chromosomes, the cell nucleus, and almost every cell in a person’s body has the same DNA.
It is made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T).
The structure of double helix DNA derives from adenine bonding with thymine and cytosine bonding with guanine.
Human DNA is made up of three billion bases, and more than 99 percent of them are the same for everyone.
The order of the bases determines what information is available for the maintenance of an organism (similar to how letters of the alphabet form sentences).
The DNA bases pair up with each other and also attach to a sugar molecule and a phosphate molecule, joining them together to form a nucleotide.
These nucleotides are arranged in two long strands that form a spiral called a double helix.
The double helix looks like a ladder, with the base pairs forming the rungs and the sugar and phosphate molecules forming vertical side pieces.
A new form of DNA was recently discovered for the first time in living human cells.
Named i-motif, the shape looks like a twisted DNA knot rather than the familiar double helix.
It’s unclear what the i-motif’s function is, but experts believe it could “read” DNA sequences and turn them into useful substances.
Source: US National Library of Medicine