Genetic history with Chinese characteristics

How two Bronze-Age tribes became the world’s 1.3 billion Han (without even changing much genetically)

Extended in part 2, Venerable Ancestors: untangling the Chinese people's hybrid Pleistocene origins (also, accompanying podcast)

The first rock-solid date in Chinese history is 1046 BC when the forces of the rebellious Zhou, barbarians from the western fringe of the civilized world, defeated the ruling Shang. The Zhou victory’s precise date, January 20th, is established through the astronomical alignment astrologers recorded for the battle. This is when the narrative fog of archaeology permanently gives way to the rich and lively vignettes of individual citizens, rulers and advisors, King Cheng, King Wu, and the Duke of Zhou. These storied figures shaped Chinese culture for thousands of years down to the modern day, and 1046 BC marks the beginning of historical China. We discern in the upstart Zhou the outline of dynasties to come, as they legitimized their rule on the grounds of an ethical right to govern, the Mandate of Heaven, rather than settling for might to simply make right.

But though the arc of Chinese civilization begins charting its ascent with the Zhou’s rise 3,000 years ago, its roots run far deeper. The modern Chinese boast of 5,000 years of history, but the oldest written attestations appear in the Oracle Bones, relics of divination rituals dating back to 1250 BC at the earliest, meaning over 3,250 years of historical documents. The importance of the Oracle Bones though lies not in their precise antiquity but in their vindication of the oral tradition of dynastic succession recorded during the Zhou: scholars had assumed the Shang dynasty to be legendary until the ancient Oracle Bones were unearthed, clearly referencing Shang rulers cited in documents dating to centuries later. Imperial Chinese historiography also records a dynasty before the Shang, the Xia, ruling from approximately 2100-1600 BC, until the Shang overthrew them. If the Xia did exist, they are most likely the Erlitou culture, an archaeological complex that flourished in the Yellow River’s middle reaches immediately before the Shang. This region would eventually give birth to classical Chinese civilization, the core of Huáxià, “the tribe of Hua and the tribe of Xia.” That civilization existed as a coherent and self-aware culture centuries before terms like “Han” (from the Han dynasty) or “Chinese” (from the Qin dynasty) existed as labels for its dominant ethnolinguistic group. Before the rise of the Empire, ancient China was more a cultural phenomenon than a political construct.

With no writing to corroborate it, the Xia’s existence may always remain conjecture, but their supposed geographical expanse corresponds perfectly to the Erlitou culture. Archaeologists cannot definitively establish the Shang as a direct successor to the Erlitou like the Zhou have been to the Shang, but Chinese archaeologists believe one of the excavated Erlitou towns was likely the Xia capital. Before the Erlitou, the Yellow River basin was dominated by another archaeological complex, the Longshan culture. From 3000 BC onward, the Longshan village-based society is identifiable by its fine black pottery, with shards scattered from Henan, the heartland of the Shang and Zhou, eastward, down the course of the Yellow River. Longshan farmers grew millet, a grain so central to the early Chinese that the character “cereal” in the Oracle Bones depicts millet. These prehistoric farmers also raised pigs and silkworms, meaning 5,000-year-old Longshan cultural traditions remain familiar hallmarks of contemporary northern Chinese life. So, even if 5,000 years of (recorded) Chinese history, starting with that etched in bone and shell, are a bit of an exaggeration, there's no denying that China's cultural roots do genuinely run that deep, if not deeper. And now, thanks to the tools of ancient DNA, we know China’s demographic and genetic roots go back even further, tens of thousands of years into the past.

Modern historical methods are overwhelmingly predicated on the emergence of written inscriptions and texts. Before literacy has always yawned narrative darkness, and only prehistorians, chiefly archaeologists, could continue the descent farther back. For decades, understanding humanity’s preliterate cultural roots (which of course account for the vast majority of our species’ existence) fell to scholars excavating and inventorying artifacts or lucky enough to happen upon human fossil remains complete enough to be reconstructed and examined. Prehistory was a sea of potshards periodically punctuated by islands of rarer artifacts, like arrowheads and an occasional human skull. But over the last twenty years, genetics has joined the historical sciences' armamentarium, ancient DNA illuminating the darkness with flares of data. Now that information can be extracted from teeth and minuscule bones, geneticists can understand evolutionary forces far back into deep time and reconstruct our specie’s genealogy with exquisite detail. This nascent field has exposed our interactions with Neanderthals, brought to our attention migrations of forgotten populations, and forced us to reimagine the origins of civilizations we had long thought we understood. Analysis of ancient DNA has revealed Europe’s multiple genetic revolutions in the last 40,000 years, and just in the past 10,000 years, the Middle East’s transformation via a great mixing between theretofore distinct human lineages as distinct as the modern Chinese are from Europeans, as well as the Indo-Aryan arrival in the Indian subcontinent less than 4,000 years ago to beget a new synthetic civilization. China’s extreme continuity, on the other hand, has been revealed to stand wholly distinct from these cases of flux. 

Unlike either modern Europeans, the scions of wave after wave of Middle Eastern and steppe migrants, or contemporary Indian peasants, who embody the fusion of invading Indo-Aryan pastoralists from Central Asia plus indigenous farmers, the modern Chinese are mostly the direct genetic descendants of people who already inhabited the very lands of their nation tens of millennia prior, from the Yellow River in the north to the Pearl River in the south. The oldest modern human bones found in China, secreted away in isolated caves, are those of their ancestors. We now know that the Han, 95% of the citizens of today’s People’s Republic of China, are scions of hunters and foragers who roamed the Yellow and Yangzi river valleys at the end of the last Ice Age, 12,000 years ago. Today’s Chinese carry DNA startlingly similar to an individual buried in Tianyun Cave, near modern Beijing, 40,000 years ago. China might not have the oldest continuous recorded history (Mesopotamia owns this distinction). But it comes close, and on the far more astonishing scale of tens of thousands of years, the Chinese people’s biological continuity knows no parallel.