Pre-Persian Iran: from the invention of agriculture to the Aryan onslaught
Prehistoric Iranians’ genetic roots and Indian entanglements
Related: Iran through the ages: civilization's eternal crossroads, We are all Zoroastrians: how Persian empires of the mind touched all humanity and One door closes, another opens: the Persian Empire’s end and the rise of the Persianate world.
Strung between Anatolia, the Levant, the Arabian peninsula, South Asia and Central Asia, the Iranian plateau exists at an essential nexus. Before 50,000 years ago it was occupied by our Neanderthal cousins, and after, it became a crossroads for modern humans both bound for the east and north to the shores of the Pacific and Siberia’s coldest depths, and retreating from the cold of the north during inclement times. The region continued to serve as a way station between east and the west down to antiquity, with both Parthians and Sasanians trading with the Roman Empire far to their west and Han China far to their east.
Iran’s role as the eastern flank of Near Eastern civilization dates to before writing itself, when the Neolithic Revolution began to transform humanity’s economic basis. At the end of the last Ice Age, 11,700 years ago, in the Near East the first groups of humans began to settle down as sedentary agriculturalists. The uplands to the north of what we today call the Fertile Crescent witnessed the advent of cultivating crops like wheat, barley and chickpeas. But farther east, in the Zagros mountains of western Iran, a form of herding centered on goats emerged as the dominant form of subsistence just after the Ice Age. These cultural practices eventually merged, as illustrated in the Hebrew Bible with the conflicts between farmers and herders in ancient Palestine.
From these initial nuclei of agricultural activity in the Near East, cultivators and pastoralists seem to have proliferated in all directions, from the Anatolian-descended Neolithic seafarers who disembarked in Britain 6,000 years ago to the farmers in Yemen’s uplands who migrated south from the Levant 5,000 years ago, eventually building monuments like the Great Dam of Marib to control the flow of water to their fields. Until recently, archaeologists debated whether agriculture saw multiple centers of origination in the Near East, and also whether farming and pastoralism spread through cultural diffusion, with the ideas of planting crops and herding goat and cattle traveling from tribe to tribe, or through the expansion of a single enterprising people. Ancient DNA has resolved this conundrum. Agriculture seems to have emerged independently among three primary population clusters in the Near East. First, in the uplands of Syria among Levantine foragers descended mostly from Natufian hunter-gatherers. Second, nearly 500 miles to the east, at a site called Ganj Dareh in modern Iran’s Zagros mountains, where a group of goat herders popularized this form of pastoralism. And last, somewhat after the Syrian adoption of agriculture, a group of foragers in central Anatolia settled down and adopted the farming lifestyle, becoming so adept that they eventually sent waves of colonists west across Europe.
Iranians before Iran
The genetics is clear that these are three very different groups with deep prior divergences, long before the Neolithic Revolution. At the end of the last Ice Age, the Zagros pastoralists were as genetically distinct from the Levantine farmers to their west as modern Chinese are from Northern Europeans. In precise statistical genetic terms, about 10% of the genetic variation among the ancient populations differentiated them from each other, roughly what separates East and West Eurasians today (the Anatolian and Levantine farmers were genetically closer to each other, though still quite distinct by modern standards). Such striking differences highlight the likelihood of relatively high viscosity of gene flow among forager cultures; prehistoric hunter-gatherers seem to have intermarried across tribes less than their farmer successors. Jared Diamond in Guns, Germs and Steel suggested that agriculture was a horrible long-term choice for our forager ancestors, leading to more war and conflict due to the accumulation of material wealth, but much of the ancient DNA evidence now points to the possibility that actually roving bands of hunter-gatherers were more xenophobic and hostile to outsiders than their farming descendants. Today, the genetic distance between Syrians and Iranians is a mere tenth of that between their prehistoric ancestors, reflecting thousands of years of migration between the various populations of West Asia.