Ribosomal DNA repeat unit polymorphism in 25 Hordeum species

Molnar, S. J. ; Gupta, P. K. ; Fedak, G. ; Wheatcroft, R. (1989) Ribosomal DNA repeat unit polymorphism in 25 Hordeum species Theoretical and Applied Genetics, 78 (3). pp. 387-392. ISSN 0040-5752

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Official URL: http://www.springerlink.com/content/j63738u2437gm8...

Related URL: http://dx.doi.org/10.1007/BF00265301


Tandemly repeated DNA sequences containing structural genes encoding ribosomal RNA (rDNA) were investigated in 25 species of Hordeum using the wheat rDNA probe pTA71. The rDNA repeat unit lengths were shown to vary between 8.5 and 10.7 kb. The number of length classes (1-3) per accession generally corresponded to the number of nucleolar organizing regions (NORs). Intraspecific variation was found in H. parodii, H. spontaneum and H. leporinum, but not in H. bulbosum. Restriction analysis showed that the positions of EcoRI, SacI and certain BamHI cleavage sites in the rRNA structural genes were highly conserved, and that repeat unit length variation was generally attributable to the intergenic spacer region. Five rDNA BamHI restriction site maps corresponded to the following groups of species: Map A-H. murinum, H. glaucum, H. leporinum, H. bulbosum, H. marinum, H. geniculatum; Map B-H. leporinum; Map C-H. vulgare, H. spontaneum, H. agriocrithon; Map D-H. chilense, H. bogdanii; and Map E-remaining 14 Hordeum species. The repeat unit of H. bulbosum differed from all other species by the presence of a HindIII site. The closer relationship of H. bulbosum to H. leporinum, H. murinum and H. glaucum than to H. vulgare was indicated by their BamHI restriction maps.

Item Type:Article
Source:Copyright of this article belongs to Springer.
Keywords:Hordeum; Barley; Ribosomal DNA; Polymorphism; Restriction Analysis
ID Code:74984
Deposited On:20 Dec 2011 04:29
Last Modified:20 Dec 2011 04:29

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