Continuous presence of proto-cereals in Anatolia since 2.3\xa0Ma, and their possible co-evolution with large herbivores and hominins

Valérie Andrieu-Ponel,Didier Bourlès,Philippe Ponel,Claire Rambeau,Amélie Vialet,Hülya Alçiçek,Serdar Mayda,Sébastien Nomade,François Demory,Cahit Helvacı,Mireille Perrin,Anne-Elisabeth Lebatard,Nicolas Boulbes,Pierre Rochette,Henri Michaud,Anne-Marie Moigne,Mehmet Cihat Alçiçek,Belinda Gambin

doi:10.1038/s41598-021-86423-8

Abstract

Cereals are a central resource for the human diet and are traditionally assumed to have evolved from wild grasses at the onset of the Neolithic under the pressure of agriculture. Here we demonstrate that cereals may have a significantly longer and more diverse lineage, based on the study of a 0–2.3 Ma, 601 m long sedimentary core from Lake Acıgöl (South-West Anatolia). Pollen characteristic of cereals is abundant throughout the sedimentary sequence. The presence of large lakes within this arid bioclimatic zone led to the concentration of large herbivore herds, as indicated by the continuous occurrence of coprophilous fungi spores in the record. Our hypothesis is that the effects of overgrazing on soils and herbaceous stratum, during this long period, led to genetic modifications of the Poaceae taxa and to the appearance of proto-cereals. The simultaneous presence of hominins is attested as early as about 1.4 Ma in the lake vicinity, and 1.8 Ma in Georgia and Levant. These ancient hominins probably benefited from the availability of these proto-cereals, rich in nutrients, as well as various other edible plants, opening the way, in this region of the Middle East, to a process of domestication, which reached its full development during the Neolithic.

Highlights

Cereals are a central resource for the human diet and are traditionally assumed to have evolved from wild grasses at the onset of the Neolithic under the pressure of agriculture
What happened in the Neolithic, when humans went from a hunter-gatherer to a farmer lifestyle? Did they reproduce conditions that existed two million years ago? Has there been a new stage of cereal speciation linked to humans? V aughan[42] emphasises that "the time scale of domestication of 10,000 years or less is a very short evolutionary time span" (p. 893)
The proto-cereal pollen of Acıgöl appears to indicate that the genetic modification of cereals could have been a natural process that appeared long before agriculture emerged, and that the conditions were already present when human populations shifted from hunter-gatherer to agricultural societies

Summary

Introduction

Cereals are a central resource for the human diet and are traditionally assumed to have evolved from wild grasses at the onset of the Neolithic under the pressure of agriculture. The simultaneous presence of hominins is attested as early as about 1.4 Ma in the lake vicinity, and 1.8 Ma in Georgia and Levant. These ancient hominins probably benefited from the availability of these proto-cereals, rich in nutrients, as well as various other edible plants, opening the way, in this region of the Middle East, to a process of domestication, which reached its full development during the Neolithic. An interdisciplinary study was carried out on the lacustrine sedimentary sequence of Acıgöl (Lakes district, SW Turkey, (Fig. 1). The oldest Homo erectus remains from Turkey (the Kocabaş skull) were discovered in the travertine deposit of Denizli 40 km W of Acıgöl lake[2,3] and dated to ca 1.2–1.6 Ma4, documenting one of the main early migratory axis of hominin

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Conclusion