Iran

Iran’s position on the Iranian plateau has made it a persistent corridor and cradle for human populations since the Middle Pleistocene. Fossil and lithic evidence from sites such as Kaldar Cave in the Zagros and the open-air localities near the Alborz Mountains indicates that hominins, probably Homo heidelbergensis or early Neanderthals, were present by at least 400,000 years ago. Later Middle Paleolithic layers at the same localities contain Levallois tools and Neanderthal remains, while Upper Paleolithic strata document the arrival of anatomically modern humans after 45,000 years ago, consistent with an inland dispersal route out of Africa that skirted the southern Caspian shore.

During the Late Pleistocene and early Holocene, the Zagros Mountains witnessed one of the world’s earliest transitions to food production. Excavations at Ganj Dareh and Sheikh-e Abad have recovered goat remains showing morphological signs of management by 10,000 BCE, while macrobotanical assemblages from Chogha Golan document the cultivation of wild barley and wheat several centuries earlier. Ancient DNA from eight individuals buried at these sites, published by Broushaki and colleagues in 2016, reveals a population genetically distinct from the Anatolian farmers who later spread into Europe; instead, these Zagros farmers carried substantial ancestry related to Caucasus hunter-gatherers and contributed significantly to the genomes of later South Asian and Iranian populations.

Population movements through the plateau continued into later prehistory. Linguistic and genetic data suggest that Indo-Iranian speakers entered from the north during the second millennium BCE, admixing with local groups whose ancestry combined Zagros Neolithic and steppe-derived components. The subsequent rise of the Elamite polity in southwestern Iran, followed by the Achaemenid and Sasanian empires, created expansive polities that facilitated gene flow across Central Asia, the Near East, and the Indian subcontinent, as shown by both historical records and strontium-isotope studies of burial populations at sites such as Persepolis and Susa.

Scientific understanding of these processes remains incomplete. The precise timing of modern human entry into the plateau is still debated because many early sites lack secure radiometric dates, and the relative contribution of Neanderthal admixture versus later Holocene migrations requires further high-coverage ancient genomes. Moreover, the extent to which the Zagros domestication center operated independently of the Levant continues to be tested through ongoing archaeobotanical and genetic research.

Taken together, Iran’s archaeological and genetic record illustrates how a single geographic crossroads shaped successive chapters of human prehistory—from the earliest dispersals of our species to the formation of expansive empires—while underscoring the mosaic nature of the Neolithic transition and the persistence of regionally distinctive ancestries into the historic era.