Comparative physical mapping of the 18S-5.8S-26S rDNA in three sorghum species

The physical locations of the 18S-5.8S-26S rDNA sequences were examined in three sorghum species by fluorescence in situ hybridization (FISH) using biotin-labeled heterologous 18S-5.8S-26S rDNA probe (pTa71). Each 18S-5.8S-26S rDNA locus occurred at two sites on the chromosomes in Sorghum bicolor (2n = 20) and S. versicolor (2n = 10), but at four sites on the chromosomes of S. halepense (2n = 40) and the tetraploid S. versicolor (2n = 20). Positions of the rDNA loci varied from the interstitial to terminal position among the four accessions of the three sorghum species. The rDNA data are useful for investigation of chromosome evolution and phylogeny. This study excluded S. versicolor as the possible progenitor of S. bicolor.Key words: Sorghum bicolor, Sorghum versicolor, Sorghum halepense, 18S-5.8S-26S rDNA, fluorescence in situ hybridization.

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Chromosomal localization and characterization of rDNA loci in the Brassica A and C genomes

Genome ◽

10.1139/g97-076 ◽

1997 ◽

Vol 40 (4) ◽

pp. 582-587 ◽

Cited By ~ 50

Author(s):

R. J. Snowdon ◽

W. Köhler ◽

A. Köhler

Keyword(s):

In Situ Hybridization ◽

Fluorescence In Situ Hybridization ◽

Ribosomal Dna ◽

Diploid Species ◽

Rdna Locus ◽

Chromosome Morphology ◽

Rdna Site ◽

A Genome ◽

Rdna Loci

Using fluorescence in situ hybridization, we located ribosomal DNA loci on prometaphase chromosomes of the diploid species Brassica rapa and Brassica oleracea and their amphidiploid Brassica napus. Based on comparisons of chromosome morphology and hybridization patterns, we characterized the individual B. napus rDNA loci according to their presumed origins in the Brassica A and C genomes. As reported in other studies, the sum of rDNA loci observed on B. rapa (AA genome) and B. oleracea (CC genome) chromosomes was one greater than the total number of loci seen in their amphidiploid B. napus (AACC). Evidence is presented that this reduction in B. napus rDNA locus number results from the loss of the smallest A genome rDNA site in the amphidiploid.Key words: Brassica, fluorescence in situ hybridization, ribosomal DNA, rDNA.

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X chromosome evolution in the suni and eland antelope: detection of homologous regions by fluorescence in situ hybridization and G-banding

Cytogenetic and Genome Research ◽

10.1159/000134580 ◽

1997 ◽

Vol 77 (3-4) ◽

pp. 218-222 ◽

Cited By ~ 10

Author(s):

T.J. Robinson ◽

W.R. Harrison ◽

Ponce de León ◽

F.F.B. Elder

Keyword(s):

In Situ Hybridization ◽

Fluorescence In Situ Hybridization ◽

X Chromosome ◽

Chromosome Evolution ◽

X Chromosome Evolution

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FISH of a maize sh2-selected sorghum BAC to chromosomes of Sorghum bicolor

Genome ◽

10.1139/g97-063 ◽

1997 ◽

Vol 40 (4) ◽

pp. 475-478 ◽

Cited By ~ 19

Author(s):

Martha I. Gómez ◽

M. Nurul Islam-Faridi ◽

Sung-Sick Woo ◽

Don Czeschin Jr. ◽

Michael S. Zwick ◽

...

Keyword(s):

In Situ Hybridization ◽

Sorghum Bicolor ◽

Fluorescence In Situ Hybridization ◽

Artificial Chromosome ◽

Single Copy ◽

Bacterial Artificial Chromosomes ◽

Extra Copy ◽

Artificial Chromosomes ◽

Sorghum Plant

Fluorescence in situ hybridization (FISH) of a 205 kb Sorghum bicolor bacterial artificial chromosome (BAC) containing a sequence complementary to maize sh2 cDNA produced a large pair of FISH signals at one end of a midsize metacentric chromosome of S. bicolor. Three pairs of signals were observed in metaphase spreads of chromosomes of a sorghum plant containing an extra copy of one arm of the sorghum chromosome arbitrarily designated with the letter D. Therefore, the sequence cloned in this BAC must reside in the arm of chromosome D represented by this monotelosome. This demonstrates a novel procedure for physically mapping cloned genes or other single-copy sequences by FISH, sh2 in this case, by using BACs containing their complementary sequences. The results reported herein suggest homology, at least in part, between one arm of chromosome D in sorghum and the long arm of chromosome 3 in maize.Key words: sorghum, maize, shrunken locus, physical mapping, fluorescence in situ hybridization, bacterial artificial chromosomes.

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FISH-mapping of rDNAs and Arabidopsis BACs on pachytene complements of selected Brassicas

Genome ◽

10.1139/g01-101 ◽

2002 ◽

Vol 45 (1) ◽

pp. 189-197 ◽

Cited By ~ 34

Author(s):

Piotr A Ziolkowski ◽

Jan Sadowski

Keyword(s):

In Situ Hybridization ◽

Physical Mapping ◽

5S Rdna ◽

Artificial Chromosome ◽

Rdna Locus ◽

Fish Analysis ◽

45S Rdna ◽

Fish Mapping ◽

Rdna Sequences

To improve resolution of physical mapping on Brassica chromosomes, we have chosen the pachytene stage of meiosis where incompletely condensed bivalents are much longer than their counterparts at mitotic metaphase. Mapping with 5S and 45S rDNA sequences demonstrated the advantage of pachytene chromosomes in efficient physical mapping and confirmed the presence of a novel 5S rDNA locus in Brassica oleracea, initially identified by genetic mapping using restriction fragment length polymorphism (RFLP). Fluorescence in situ hybridization (FISH) analysis visualized the presence of the third 5S rDNA locus on the long arm of chromosome C2 and confirmed the earlier reports of two 45S rDNA loci in the B. oleracea genome. FISH mapping of low-copy sequences from the Arabidopsis thaliana bacterial artificial chromosome (BAC) clones on the B. oleracea chromosomes confirmed the expectation of efficient and precise physical mapping of meiotic bivalents based on data available from A. thaliana and indicated conserved organization of these two BAC sequences on two B. oleracea chromosomes. Based on the heterologous in situ hybridization with BACs and their mapping applied to long pachytene bivalents, a new approach in comparative analysis of Brassica and A. thaliana genomes is discussed.Key words: Brassicaceae, pachytene chromosomes, FISH, rDNA, BACs.

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