A new study combining genetic, palaeoecological, and archaeological evidence has unveiled the Persian Plateau as a pivotal geographic location serving as a hub for Homo sapiens during the early stages of their migration out of Africa.

This revelation sheds new light on the complex journey of human populations, challenging previous understandings of our species' expansion into Eurasia.

The study, published in Nature Communications, highlights a crucial period between approximately 70,000 to 45,000 years ago when human populations did not uniformly spread across Eurasia, leaving a gap in our understanding of their whereabouts during this time frame.

Key findings from the research include:

  • The Persian plateau as a hub for early human settlement: Using a novel genetic approach combined with palaeoecological modelling, the study revealed the Persian Plateau as the region where from population waves that settled all of Eurasia originated.

  • This region emerged as a suitable habitat capable of supporting a larger population compared with other areas in West Asia.

  • Genetic resemblance in ancient and modern populations: The genetic component identified in populations from the Persian Plateau underlines its long-lasting differentiation in the area, compatible with the hub nature of the region, and is ancestral to the genetic components already known to have inhabited the Plateau.

  • Such a genetic signature was detected thanks to a new approach that disentangles 40,000 years of admixture and other confounding events. This genetic connection underscores the Plateau's significance as a pivotal location for early human settlement and subsequent migrations.

Study co-author Professor Michael Petraglia, Director of Griffith University's Australian Research Centre for Human Evolution, provided a much clearer picture of these early human movements.1

  • 1. "Our multidisciplinary study provides a more coherent view of the ancient past, offering insights into the critical period between the Out of Africa expansion and the differentiation of Eurasian populations," Professor Petraglia said. "The Persian Plateau emerges as a key region, underlining the need for further archaeological explorations."
Pebdeh Cave located in the southern Zagros Mountains. Pebdeh was occupied by hunter-gatherers as early as 42,000 years ago.
Pebdeh Cave located in the southern Zagros Mountains. Pebdeh was occupied by hunter-gatherers as early as 42,000 years ago. © Mohammad Javad Shoaee

Leonardo Vallini, Carlo Zampieri, Mohamed Javad Shoaee, Eugenio Bortolini, Giulia Marciani, Serena Aneli, Telmo Pievani, Stefano Benazzi, Alberto Barausse, Massimo Mezzavilla, Michael D. Petraglia, Luca Pagani. The Persian plateau served as hub for Homo sapiens after the main out of Africa dispersal. Nature Communications, 2024; 15 (1) DOI: 10.1038/s41467-024-46161-7

A combination of evidence, based on genetic, fossil and archaeological findings, indicates that Homo sapiens spread out of Africa between ~70-60 thousand years ago (kya). However, it appears that once outside of Africa, human populations did not expand across all of Eurasia until ~45 kya. The geographic whereabouts of these early settlers in the timeframe between ~70-60 to 45 kya has been difficult to reconcile. Here we combine genetic evidence and palaeoecological models to infer the geographic location that acted as the Hub for our species during the early phases of colonisation of Eurasia. Leveraging on available genomic evidence we show that populations from the Persian Plateau carry an ancestry component that closely matches the population that settled the Hub outside Africa. With the paleoclimatic data available to date, we built ecological models showing that the Persian Plateau was suitable for human occupation and that it could sustain a larger population compared to other West Asian regions, strengthening this claim.

Fig. 1: Relationship and legacy of the West and East Eurasian Core populations.
Fig. 1: Relationship and legacy of the West and East Eurasian Core populations. - Summary of the major population events (A) and schematic representation of our reference space and expected position of admixed and unadmixed populations (B – note that this panel is a rotation of the blue and red portion of A); derived allele sharing of each ancient or modern individual/population with Kostenki14 and Tianyuan (C); East Asians in red, Oceanians in orange, Native Americans in pink, South Asians in yellow, Northern South Asians in green, West Eurasians in blue, Levantines in cornflowerblue, ancient samples in black (N stands for Neolithic, WHG for Western Hunter Gatherers).