Adaptive ribosomal DNA polymorphism in wild barley at a mosaic microsite, Newe Ya'ar in Israel

Gupta, Pushpendra Kumar ; Sharma, Shailendra ; Kumar, Sundip ; Balyan, Harindra Singh ; Beharav, Alex ; Nevo, Eviatar (2004) Adaptive ribosomal DNA polymorphism in wild barley at a mosaic microsite, Newe Ya'ar in Israel Plant Science, 166 (6). pp. 1555-1563. ISSN 0168-9452

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Official URL: http://linkinghub.elsevier.com/retrieve/pii/S01689...

Related URL: http://dx.doi.org/10.1016/j.plantsci.2004.02.017

Abstract

In eukaryotic genomes, ribosomal DNA is organized in tandem repeat units at the nucleolar organizing regions (NORs) on each satellited chromosome. Each repeat unit consists of a coding region and an intergenic spacer (IGS), the latter generally varying in length at different loci of the same genotype and also at the same locus in different genotypes. The spacer length variants (slvs) are sometimes correlated with climatic and ecological variables. In a study of 42 accessions of wild barley (Hordeum spontaneum) collected from four different microniches (sun-deep soil, sun-shallow soil, shade-deep soil and shade-shallow soil) at the Newe Ya'ar microsite (3182 m2), in Israel, we observed eight slvs constituting 10 different rDNA phenotypes, correlated with edaphic conditions prevalent at the four microniches. We conclude that rDNA diversity in wild barley is distributed nonrandomly and adaptively in the four microniches of Newe Ya'ar. A novel feature in this study is also the homogenization of IGS length at the two loci located at two nonhomologous chromosomes. Fluorescence in situ hybridization (FISH), was used to rule out the possibility of loss of one of the two NOR loci.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:rDNA; Spacer Length Variants; Homogenization; Natural Selection; Hordeum Spontaneum
ID Code:12874
Deposited On:11 Nov 2010 14:10
Last Modified:11 Nov 2010 14:10

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