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GrainGenes Gene Class Report: Nucleolus organizer regions

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Gene Class
Nucleolus organizer regions
Reference
ReferenceMcIntosh RA et al. (1995) Catalogue of gene symbols for wheat. Proceedings of the 8th International Wheat Genetics Symposium 1333-1500.
[ Show all 11 ]
Abbreviation
Nor
Character affected
Ribosomal RNA
Orthologous Gene Set
Nor-1
Nor-2
Nor-3
Nor-4
Nor-5
Gene
Nor-R1 (Secale)
[ Show all 24 ]
Allele
Nor-B1a (Triticum)
[ Show all 17 ]
Locus
Nor-R1
[ Show all 12 ]
Clone
pTa250.15
Comment
18S-5.8S-26S rRNA genes.
NORs have been observed as secondary constrictions associated with nucleoli on satellited chromosomes (e.g., 167), and by in situ hybridization to chromosome spreads (34, 207, 721) of 18.S-5.8S-26S ribosomal-DNA probes (32, 301). Allelic variation in gene number has been demonstrated at all wheat Nor sites and at Nor-R1 by filter (252) and in situ hybridization (720).
Allelic variants of the Nor loci are detected by hybridization of rDNA probes to restriction endonuclease-treated DNA on Southern blots (33, 203, 657, 1005). Alleles Nor-B2a to Nor-B2f were identified using Taq1 digests of genomic DNAs hybridized to derivatives of the plasmid pTa250 (301) containing spacer-DNA fragments pTa250.4 (252, 657) and pTa250.15 (203).
Other variants may have been isolated (1005) using BamH1/EcoR1 double digests and pTa71 (301). The variants Nor1a and Nor2a in Maris Huntsman, Nor1b and Nor2b in Bezostaya 1, and Nor1c and Nor2c in Maris Ranger and Cappelle Desprez (1005) may or may not be equivalent to the Nor-B1 and Nor-B2 alleles listed in the Catalogue of Gene Symbols for Wheat (9441).
Wheat Gene Catalog Reference
[ Hide all but 1 of 11 ]
9441
ReferenceMcIntosh RA et al. (1995) Catalogue of gene symbols for wheat. Proceedings of the 8th International Wheat Genetics Symposium 1333-1500.
657
ReferenceMay CE and Appels R (1987) Variability and genetics of spacer DNA sequences between the ribosomal-RNA genes of hexaploid wheat (Triticum aestivum). Theoretical and Applied Genetics 74:617-624.
203
ReferenceDvorak J and Appels R (1986) Investigation of homoeologous crossing over and sister chromatid exchange in the wheat NOR-B2 locus coding for rRNA and GLI-B2 locus coding for gliadins. Genetics 113:1037-1056.
1005
ReferenceSnape JW et al. (1985) Intra-chromosomal mapping of the nucleolar organiser region relative to three marker loci on chromosome 1B of wheat (Triticum aestivum). Theoretical and Applied Genetics 69:263-270.
207
ReferenceDvorak J et al. (1984) The distribution of the ribosomal RNA genes in the Triticum speltoides and Elytrigia elongata genomes. Canadian Journal of Genetics and Cytology 26:628-632.
721
ReferenceMiller TE et al. (1983) The identification of the nucleolar organizer chromosomes of diploid wheat. Theoretical and Applied Genetics 65:145-147.
33
ReferenceAppels R and Dvorak J (1982) The wheat ribosomal DNA spacer region: its structure and variation in populations and among species. Theoretical and Applied Genetics 63:337-348.
720
ReferenceMiller TE et al. (1980) Nucleolus organiser variation in wheat and rye revealed by in situ hybridisation. Heredity 45:377-382.
301
ReferenceGerlach WL and Bedbrook JR (1979) Cloning and characterisation of ribosomal RNA genes from wheat and barley. Nucleic Acids Research 7:1869-1886.
252
ReferenceFlavell RB and Smith DB (1974) The role of homoeologous group 1 chromosomes in the control of rRNA genes in wheat. Biochemical Genetics 12:271-279.
167
ReferenceCrosby AR (1957) Nucleolar activity of lagging chromosomes in wheat. American Journal of Botany 44:813-822.

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