Molecular phylogeography of domesticated barley traces expansion of agriculture in the Old World

Barley (Hordeum vulgare ssp. vulgare) was first cultivated 10,500 years ago in the Fertile Crescent and is one of the founder crops of Eurasian agriculture. Phylogeographic analysis of five nuclear loci and morphological assessment of two traits in >250 domesticated barley accessions reveals that landraces found in South and East Asia are genetically distinct from those in Europe and North Africa. A Bayesian population structure assessment method indicates that barley accessions are subdivided into 6 clusters, and that barley landraces from 10 different geographical regions of Eurasia and North Africa show distinct patterns of distribution across these clusters. Using haplotype frequency data, it appears that the Europe/North Africa landraces are most similar to the Near East population (FST = 0.15) as well as wild barley (FST = 0.11) and are strongly differentiated from all other Asian populations (FST = 0.34 to 0.74). A neighbor-joining analysis using these FST estimates also supports a division between Europe, North African and Near East barley types from more easterly Asian accessions. There is also differentiation in the presence of a naked caryopsis and spikelet row number between eastern and western barley accessions. The data support the differential migration of barley from two domestication events that led to the origin of barley – one in the Fertile Crescent and another further east, possibly at the eastern edge of the Iranian Plateau - with European and North African barley largely originating from the former while much of Asian barley arising from the latter. This suggests that cultural diffusion or independent innovation are responsible for the expansion of agriculture to areas of South and East Asia during the Neolithic Revolution.

Key Words: Fertile Crescent, Neolithic Revolution, crop origins, domestication, phylogeography

This article has been cited by other articles:

				S. Taketa, S. Amano, Y. Tsujino, T. Sato, D. Saisho, K. Kakeda, M. Nomura, T. Suzuki, T. Matsumoto, K. Sato, et al. Barley grain with adhering hulls is controlled by an ERF family transcription factor gene regulating a lipid biosynthesis pathway PNAS, March 11, 2008; 105(10): 4062 - 4067. [Abstract] [Full Text] [PDF]

Online ISS 1091-6490
Copyright 2008 by the Genetics Society of America
phone: 412-268-1812   fax: 412-268-1813   email: genetics-gsa{at}andrew.cmu.edu