A remarkable discovery has emerged from a 7,100-year-old skeleton found in China, shedding light on a previously theorized but unproven ghost lineage. This groundbreaking study, which analyzed ancient skeletons, aims to map the complex genetic history of central China. The individual at the heart of this finding is an Early Neolithic woman, whose DNA provides significant clues about the origins of the Tibetan people.
The skeleton, unearthed at the Xingyi archaeological site located in southwestern China's Yunnan province, represents a pivotal piece in understanding ancient human genetics. According to study co-author Qiaomei Fu, a paleontologist at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, there were likely more individuals like her, yet they remain unexamined. The research, published on May 29 in the journal Science, analyzed 127 human genomes from the region, most of which date back between 1,400 and 7,150 years.
Yunnan province is characterized by the highest ethnic and linguistic diversity in all of China, making it a critical area for researchers studying ancient populations. The ancient humans that inhabited this region could provide key insights into the prehistoric populations of East and Southeast Asia. Among the pressing questions are the origins of the people residing on the Tibetan Plateau, particularly because previous studies have indicated that Tibetans possess a unique ghost ancestry alongside northern East Asian ancestry.
At the Xingyi site, archaeologists discovered numerous burials spanning from the Neolithic period (7000 to 2000 B.C.) to the Bronze Age (2000 to 770 B.C.). Among these, they found the female skeleton, known as Xingyi_EN, buried without any grave goods. Carbon dating confirmed her existence around 7,100 years ago, and an isotope analysis of her diet suggested she was likely a hunter-gatherer.
However, the genomic analysis of Xingyi_EN revealed surprising results: her ancestry closely resembled a diverged Asian population rather than modern East and South Asians. This finding points to a previously unknown lineage, termed the Basal Asian Xingyi lineage, which diverged from other human populations at least 40,000 years ago. The existence of a ghost population is defined as a group inferred through statistical analysis of ancient and modern DNA, without skeletal remains to substantiate their existence.
Interestingly, the ancestry of Xingyi_EN does not match that of well-documented ancient populations like Neanderthals or Denisovans, who contributed some ghost DNA to modern humans. Instead, her lineage suggests a long period of isolation from other groups, allowing this unique ancestry to persist without interbreeding. Nevertheless, at some point, her relatives did mix with other East Asian groups, leading to a population that has contributed genes to present-day Tibetans.
While these findings are compelling, the researchers urge caution in interpreting the genetic evidence, which is derived from a single individual. Further research is essential to fully elucidate the connections between Xingyi_EN and the Tibetan ghost lineage. This study not only enriches our understanding of ancient human populations but also highlights the complexities of human ancestry in China and beyond.
