Tibet as a Potential Domestication Center of Cultivated Barley of China

Xifeng Ren,Genlou Sun,Eviatar Nevo,Dongfa Sun,David Caramelli

doi:10.1371/journal.pone.0062700

Xifeng Ren, Genlou Sun + Show 3 more

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https://doi.org/10.1371/journal.pone.0062700

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Abstract

The importance of wild barley from Qinghai-Tibet Plateau in the origin and domestication of cultivated barley has long been underestimated. Population-based phylogenetic analyses were performed to study the origin and genetic diversity of Chinese domesticated barley, and address the possibility that the Tibetan region in China was an independent center of barley domestication. Wild barley (Hordeum vulgare ssp. spontaneum) populations from Southwest Asia, Central Asia, and Tibet along with domesticated barley from China were analyzed using two nuclear genes. Our results showed that Tibetan wild barley distinctly diverged from Southwest Asian (Near East) wild barley, that Central Asian wild barley is related to Southwest Asian wild barley, and that Chinese domesticated barley shares the same haplotypes with Tibetan wild barley. Phylogenetic analysis showed a close relationship between Chinese domesticated barley and the Tibetan wild barley, suggesting that Tibetan wild barley was the ancestor of Chinese domesticated barley. Our results favor the polyphyletic origin for cultivated barley.

Highlights

Barley, a founder crop of old World Neolithic food production, and one of the earliest domesticated crops [1,2], is one of the main cereals of the Mediterranean belt of agriculture
It has been reported that Hordeum vulgare ssp. spontaneum is distributed in the east-Mediterranean basin and the west Asiatic countries, penetrating into the Aegean region and North Africa to Morocco, and extends eastwards to central Asian areas and Tibet of China [2,17,18]
Analysis of genetic diversity of hordein in wild close relatives of barley from Tibet supported the hypothesis that the Qinghai-Tibet Plateau and its vicinity are the center for the cultivated barley in the Oriental region [58]

Summary

Introduction

A founder crop of old World Neolithic food production, and one of the earliest domesticated crops [1,2], is one of the main cereals of the Mediterranean belt of agriculture. Spontaneum in sites other than the Fertile Crescent such as Tibet, central Asia, Morocco, Libya, Egypt, Crete, and Ethiopia has challenged the prevalent single origin theory on the origin of barley [9,10,11,12,13,14,15,16]. Spontaneum is distributed in the east-Mediterranean basin and the west Asiatic countries, penetrating into the Aegean region and North Africa to Morocco, and extends eastwards to central Asian areas and Tibet of China [2,17,18]. Recent molecular evidence suggested Central Asia, 1,500–3,000 km farther east from the Fertile Crescent [12], and Tibet of China [16] as additional centers of wild barley domestications, and supported multiple origins of cultivated barley. Morrell and Clegg [12], and Saisho and Purugganan [19] suggested that a second domestication occurred east of the Fertile Crescent that contributed to Central and East Asian barleys

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