DNA sequence variation of wild barley Hordeum spontaneum (L.) across environmental gradients in Israel

G. Bedada, A. Westerbergh, E. Nevo, A. Korol, K. J. Schmid

Research output: Contribution to journalArticlepeer-review

Abstract

Wild barley Hordeum spontaneum (L.) shows a wide geographic distribution and ecological diversity. A key question concerns the spatial scale at which genetic differentiation occurs and to what extent it is driven by natural selection. The Levant region exhibits a strong ecological gradient along the North-South axis, with numerous small canyons in an East-West direction and with small-scale environmental gradients on the opposing North- and South-facing slopes. We sequenced 34 short genomic regions in 54 accessions of wild barley collected throughout Israel and from the opposing slopes of two canyons. The nucleotide diversity of the total sample is 0.0042, which is about two-thirds of a sample from the whole species range (0.0060). Thirty accessions collected at 'Evolution Canyon' (EC) at Nahal Oren, close to Haifa, have a nucleotide diversity of 0.0036, and therefore harbor a large proportion of the genetic diversity. There is a high level of genetic clustering throughout Israel and within EC, which roughly differentiates the slopes. Accessions from the hot and dry South-facing slope have significantly reduced genetic diversity and are genetically more distinct from accessions from the North-facing slope, which are more similar to accessions from other regions in Northern Israel. Statistical population models indicate that wild barley within the EC consist of three separate genetic clusters with substantial gene flow. The data indicate a high level of population structure at large and small geographic scales that shows isolation-by-distance, and is also consistent with ongoing natural selection contributing to genetic differentiation at a small geographic scale.

Original languageEnglish
Pages (from-to)646-655
Number of pages10
JournalHeredity
Volume112
Issue number6
DOIs
StatePublished - Jun 2014

Bibliographical note

Funding Information:
We are grateful to Claudia Wenderoth and Domenica Schnabelrauch for the technical help, and to Andreas Weber for the greenhouse plant cultivation. This work was funded by the Minerva Foundation short-term fellowship and a FORMAS Grant to KJS. EN thanks the Ancell Teicher Research Foundation of Genetics and Molecular Evolution. A Beiles, T Günther and S Hübner provided comments on the manuscript. The constructive comments of two reviewers are gratefully acknowledged.

Keywords

  • DNA sequence variation
  • Evolution Canyon
  • population structure
  • wild barley

ASJC Scopus subject areas

  • Genetics(clinical)
  • Genetics

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