DNA From a 7,100-year-old Individual Could Be the First Known Representative of a ‘Ghost’ Population
An eye-opening update has come about the origin of modern humans in Tibet from China. New research indicates that a mysterious group originated in China’s Yunnan province around 7,100 years ago, according to The Independent. This population possibly became the ancestors of modern Tibetans. Findings regarding this group have been published in Science.
The study showcased that modern Tibetans have genes from northern East Asians and this unknown 'ghost' group. For the examination, researchers sequenced DNA from around 125 individuals who resided in Yunnan province somewhere between 7,100 and 1,500 years ago. During the sequencing, experts detected a 7,100-year-old individual that was genetically distinct from most modern East Asians. Researchers believe that this individual was part of the 'ghost' population.
This research helps in solving a long-standing mystery about the origin of Tibetans, stated South China Morning Post. It has long been assumed that 80% of the Tibetan population's genetic composition comes from northern Chinese populations dating back 9,500 to 4,000 years ago, and the remaining 20% belongs to a 'ghost ancestry' as labelled by scholars. This assumption had never been validated before the study.
To garner insights about the 'ghost ancestry, ' experts began exploring evidence from Yunnan. The location got picked because it was placed at the intersection between the Tibetan Plateau, Southeast Asia, as well as southern China, and also exhibited the most ethnic and linguistic diversity across China. In total, DNA was taken and analyzed from 17 sites in Yunnan. The 7,100-year-old human remain was found at the Xingyi archaeological site in central Yunnan. This human has now been dubbed 'Basal Asian Xingyi ancestry' and is speculated to be one of the 'ghost' ancestors.
Researchers were ecstatic about the finding, as this is the first time the 'ghost' population hypothesis has been proven through evidence. Analysis showcased that this lineage diverged from other Asian populations around 40,000 years ago. Descendants of this lineage survived for a long time in Yunnan, at least until 7,100 years ago. The pathway of 'Basal Asian Xingyi ancestry' could not be tracked beyond Yunnan, but its genetic component could be traced in modern Tibetans.
The study has helped researchers in somewhat bridging the gaps present in the understanding of modern populations' genetic origin, according to The Independent. Researchers think that individuals from 'Basal Asian Xingyi ancestry' managed to survive in these southern regions because of a relatively stable climate during the Ice Age, compared to other areas.
The examination also revealed that a unique “central Yunnan” ancestry, which was significantly distinct from Southern and Northern East Asian groups, appeared around 5,500 years ago. This implies that the group had a presence here way before agriculture came into being. The group could be traced in the genes of the population speaking Austroasiatic languages today, which are spread far and wide. This implies that demographic expansions took place long before farming. Researchers want to explore central Yunnan and the nearby Red River Valley for more evidence, so that they can gain further insights about Austroasiatic prehistory.