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GrainGenes Reference Report: CHR-103-179

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Reference
CHR-103-179
Title
New 18S.26S ribosomal RNA gene loci: chromosomal landmarks for the evolution of polyploid wheats
Journal
Chromosoma
Year
1994
Volume
103
Pages
179-185
Author
Jiang JM
Gill BS
Jiang J
Gill B
Type
Article
Abstract
Three new 18S-26S rRNA gene loci were identified in common wheat by sequential N-banding and in situ hybridization (ISH) analysis Locus Nor-A7 is located at the terminal area of the long arm of 5A in both diploid and polyploid wheats Locus Nor-B6 is located in N-band 1BL25 of the long arm of chromosome 1B in Triticum turgidum and Triticum aestivum ISH sites, similar to Nor-B6, were also detected on the long arms of chromosomes 1G in Triticum timopheevii and 1S in Aegilops speltoides, but their locations on the chromosomes were different from that of Nor-B6, indicating possible chromosome rearrangements in 1GL and 1BL during evolution The third new locus, Nor-D8, was only found on the short arm of chromosome 3D in the common wheat Wichita The loss of rRNA gene locus Nor-A3 and gain of repetitive DNA sequence pSc119 on the terminal part of 5AS suggest a structural modification of 5AS. Comparative studies of the location of the 18S.26S rRNA gene loci in polyploid wheats and putative A and B (G) genome progenitor species support the idea that: (1) Triticum monococcum subsp. urartu is the donor of both the A and At genome of polyploid wheats. (2) Ae. speltoides is closer to the B and G genome of polyploid wheats than Aegilops longissima and is the most probable progenitor of these two genomes.
Keyword
aegilops squarrosa
[ Show all 14 ]
Gene Catalogue Number
9502
Cited in
ReferenceMcIntosh RA et al. (1995) Catalogue of gene symbols for wheat, 1995 supplement Annual Wheat Newsletter.