Since its discovery in 2012, the ancient city of Shimao in western China has surprised archaeologists with its scale and size. Its stone walls, built around 2200 B.C.E., shelter a city and central palace that spreads over 4 square kilometers, larger than any other settlement in China at the time.
Shimao’s influence on later Chinese civilization can be seen in everything from stone carving and jade ornaments to urban planning and architecture. But who actually built it?
Scientists had long wondered whether people from China’s Yellow River Valley, where later Chinese dynasties had their roots, also founded Shimao and its surrounding settlements. DNA recovered from 169 people buried at and around the site, described today in Nature, suggest its builders were indeed locals, and that some of the innovations adopted by later Chinese cultures began in Shimao’s rugged terrain.
The results suggest the region’s population didn’t change much over time, says University of Oxford archaeologist Jessica Rawson, who was not involved with the work. “This reinforces the idea that China has retained a stable population despite many northern intrusions.”
Located just 1 kilometer from where later empires built the Great Wall of China to protect against attacking nomads, the hilly region has usually been seen as a remote frontier. “It’s not considered the cradle of Chinese civilization,” says Zhouyong Sun, an archaeologist at the Shaanxi Academy of Archaeology.
To test that theory, geneticists compared the DNA of individuals who lived in the region 1000 years before Shimao was built with those buried in tombs nestled in the city’s rugged hills and valleys. The DNA was a close match, proof that the people who built the city were descended from locals, not recent transplants. “That tells us there wasn’t a big migration,” says Qiaomei Fu, a geneticist at the Chinese Academy of Sciences who led the study.
Advertisement
At the same time, Shimao territory lay along a key route for technology and people from farther west to enter China. Around the time the city was at its peak, artifacts and animal bones show people there herded sheep and cattle and adopted the techniques needed to make tools and weapons out of bronze—key technologies first developed far to the west that reached the rest of China via the Shimao region. “[Shimao] is seen as a crucial link for the spread of metallurgy into China,” Sun says.
Recent DNA studies from Europe have shown the spread of major technologies such as agriculture and metalworking were accompanied by dramatic migrations. Archaeologists, therefore, expected to see genetic evidence for people moving from the steppe into the Shimao region, bringing bronzeworking and herding with them.
Yet the new study again shows the Shimao’s genetic makeup didn’t change much despite these massive technological shifts. “Now we need to look into other possible explanations than ‘new people came,’” says Zichan Wang, an archaeologist at the University of California, Los Angeles (UCLA) who was not part of the research team.
Small numbers of migrants may still have played a big role, says Min Li, a UCLA archaeologist who was also not part of the new study. A handful of metalworkers from the steppes to the north could have been enough to introduce bronze to Shimao and beyond, he says. “I don’t think these DNA results can account for the extraordinary innovations at Shimao,” Li says. “There must be more diversity there that the DNA analysis didn’t catch.”
The genetic analysis also offers clues to the organization of Shimao’s ruling class. The men in many of the city’s richest tombs were related. Their shared Y chromosomes suggest power and status was passed from father to son, indicating what anthropologists call a patrilineal society. In one group of Shimao tombs, researchers could tell there was a sort of dynasty at play, with four generations of fathers and sons buried close to one another.
Gender also appeared to play a role in bloody rituals at the site. Early work at Shimao uncovered the severed heads of more than 80 people piled into sacrificial pits under the city’s massive eastern gate. Based on examinations of the skulls, researchers concluded at the time that all belonged to young women. DNA from 10 heads buried in the pit, however, reveals that nine belonged to men.
Members of Shimao’s ruling class were often buried with women lying next to them, likely retainers or concubines killed and buried to accompany the men into the afterlife. In a grim detail, DNA recovered from these attendants revealed some of the women were related, perhaps members of the same family destined to die with their masters over multiple generations. “We assumed they were slaves,” Li says, “but to have them be genetically related and put into the graves is disturbing.”
Rawson says the genetic results alone can’t explain the practices of past people. In parts of ancient China and other cultures, a man’s wife or partner was expected to follow him into the afterlife. A pit full of young men’s skulls is clear evidence of human sacrifice; a woman buried in a man’s tomb might be something else. “We have to be careful—their belief system is not our belief system,” she says. “We’re not in a position yet to understand what’s going on.”
