scholarly journals Evolutionary conservation of the transcribed spacer sequences of the rDNA repeat unit in three species of the genus Aspergillus.

1994 ◽  
Vol 41 (1) ◽  
pp. 73-77 ◽  
Author(s):  
P Borsuk ◽  
M Gniadkowski ◽  
R Kucharski ◽  
M Bisko ◽  
M Kanabus ◽  
...  
Keyword(s):  
Repeat Unit ◽  
Evolutionary Conservation ◽  
Secondary Structures ◽  
Aspergillus Species ◽  
Rdna Repeat ◽  
Rdna Repeat Unit ◽  
High Degree

We have cloned and sequenced the two intervening transcribed spacers in the rDNA repeat unit of three Aspergillus species--A. nidulans, A. awamori and A. wentii. The A. wentii and A. awamori spacers are almost identical and share a high degree of homology with the A. nidulans spacers. All spacers have a high G-C content (66%-76%) and the potential of forming complex secondary structures, which may indicate that they play a role in the maturation of pre-rRNA molecules.

Cloning and characterization of the rDNA repeat unit of Podospora anserina

1985 ◽  
Vol 199 (1) ◽  
pp. 154-157 ◽  
Author(s):  
N. Labat ◽  
M. Perrot ◽  
J. Bégueret
Keyword(s):  
Repeat Unit ◽  
Podospora Anserina ◽  
Rdna Repeat ◽  
Rdna Repeat Unit

Cloning of the rDNA repeat unit from a British entomopathogenic nematode (Steinernematidae) and its potential for species identification

Parasitology ◽  
1993 ◽  
Vol 107 (5) ◽  
pp. 529-536 ◽  
Author(s):  
A. P. Reid ◽  
W. M. Hominick
Keyword(s):  
Entomopathogenic Nematode ◽  
Repeat Unit ◽  
Unit Length ◽  
Soil Survey ◽  
Rdna Repeat ◽  
Dna Repeat ◽  
Length Polymorphisms ◽  
Rdna Repeat Unit ◽  
Unique Restriction ◽  
Plasmid Puc18

SUMMARYThe entire ribosomal DNA repeat unit of a steinernematid species (Nashes isolate) was cloned as three separate EcoR I fragments in the plasmid pUC18. An equimolar cocktail of these three clones was used to identify Steinernema species on Southern blots as each species displays its own unique restriction fragment length polymorphisms. The clones also identified two new species isolated in a soil survey of coastal regions of Britain. One of the clones (pSn4.0) can detect length heterogeneities in the rDNA repeat unit of various isolates of some of the species, particularly the most common in the United Kingdom, S. feltiae. These differences in the rDNA repeat unit length remained constant over several years for one isolate of S. feltiae, but were different for each of the geographical isolates studied to date.

scholarly journals Molecular and FISH analysis of 45S rDNA on BAC molecule of Saccharina Japonica

2021 ◽  
Author(s):  
Peng-Fei Liu ◽  
Yan-Hui Bi ◽  
Li Liu ◽  
Zhi-Gang Zhou
Keyword(s):  
Physical Map ◽  
Repeat Unit ◽  
Gc Content ◽  
Intergenic Spacer ◽  
Saccharina Japonica ◽  
Fish Analysis ◽  
45S Rdna ◽  
Rdna Repeat ◽  
Bac Clone ◽  
Rdna Repeat Unit

Abstract IGS is abundant in polymorphism, which is widely used in the analysis of intraspecific genetic diversity and phylogenetic relationships among geographical populations. In this study, the 45S rDNA repeat unit of Saccharina japonica was obtained for the first time by BAC clone sequencing. The total length of 45S rDNA repeat unit of S. japonica was 8995 bp, including 5420 bp of 18s-5.8s-25s rDNA and 3575 bp of IGS (Intergenic Spacer), with the GC content of 51.4%. IGS was composed of 465 bp 3’-outer transcribed spacer (ETS), 874 bp 5’-ETS, and 2236 bp non transcribed spacer (NTS), with the GC content of 50.1%.Fiber-FISH (fiber-fluorescence in situ hybridization, fiber-FISH) analysis of 45S rDNA on the BAC molecule of female gametophytes of S. japonica illustrated that each fiber had at least five continuous moniliform hybridization signal points, indicating the distribution of 45S rDNA repeat unit on the bacterial artificial chromosome. This study provided a new candidate molecular marker for detecting intraspecific polymorphisms of S. japonica, and the successful fiber-FISH analysis of 45S rDNA on BAC molecule would contribute to the construction of the physical map and Map-based cloning of this kelp.

scholarly journals Molecular Structure of rDNA Repeat Unit inMagnaporthe grisea

2000 ◽  
Vol 64 (8) ◽  
pp. 1733-1736 ◽  
Author(s):  
Teruo SONE ◽  
Satoru FUKIYA ◽  
Megumi KODAMA ◽  
Fusao TOMITA
Keyword(s):  
Molecular Structure ◽  
Repeat Unit ◽  
Rdna Repeat ◽  
Rdna Repeat Unit

A New rDNA Repeat Unit in Human Giardia

1994 ◽  
Vol 41 (6) ◽  
pp. 639-642 ◽  
Author(s):  
JACQUELINE A. UPCROFT ◽  
ANDREW HEALEY ◽  
PETER UPCROFT
Keyword(s):  
Repeat Unit ◽  
Rdna Repeat ◽  
Rdna Repeat Unit

Polymorphism in ribosomal DNA repeat units of 12 Hordeum species

Genome ◽  
1989 ◽  
Vol 32 (6) ◽  
pp. 1124-1127 ◽  
Author(s):  
Stephen J. Molnar ◽  
George Fedak
Keyword(s):  
Ribosomal Dna ◽  
Repeat Unit ◽  
Unit Length ◽  
Intergenic Spacer ◽  
Rdna Repeat ◽  
Repeat Units ◽  
Dna Repeat ◽  
Rdna Repeat Unit ◽  
Bamhi Restriction Site ◽  
Hordeum Species

Total genomic DNA was isolated from leaves of individual accessions of 12 Hordeum species. SacI, HindIII, and BamHI restriction fragments hybridizing to the wheat rDNA probe pTA71 were compared. Thirteen rDNA repeat unit length variants were recovered, which combined to produce 11 distinct phenotypes. All rDNA repeat units had two SacI sites and no HindIII sites. The rDNA repeat units of H. secalinum, H. hrasdanicum, and H. distichum all had 3 BamHI sites, but in different configurations. The rDNA repeat units of the other species had at least 4 BamHI sites. Ladders of small hybridizing fragments in 8 of 9 of the latter accessions indicated the presence of occasional BamHI sites in some subrepeats within the intergenic spacer regions of the rDNA repeat units. Different distributions of BamHI restriction site maps within the Hordeum sections strengthen the concept of using variation in rDNA restriction sites as a taxonomic character.Key words: Hordeum, ribosomal DNA, polymorphism.

A rapid means of identifying wild rice species DNA using dot blots and genome-specific rDNA probes

Genome ◽  
1998 ◽  
Vol 41 (3) ◽  
pp. 391-395 ◽  
Author(s):  
C L McIntyre ◽  
B C Winberg
Keyword(s):  
Repeat Unit ◽  
Rice Genome ◽  
Intergenic Spacer ◽  
Size Class ◽  
Rdna Repeat ◽  
Wild Rice Species ◽  
Rdna Repeat Unit ◽  
Oryza Latifolia ◽  
Bamhi Site ◽  
Oryza Australiensis

Intergenic spacer fragments from the rDNA repeat unit were isolated from a single accession of each of 9 species that cover the range of genomes found in the Oryza genus (A-F). Seven of the 9 species contained 1 size class of rDNA repeat unit only, while Oryza sativa and Oryza latifolia contained 3 and 2 size classes, respectively, of which fragments were cloned for the major size class only. Oryza australiensis contained an additional BamHI site in the intergenic spacer. Dot blots were prepared and hybridised with a repeat unit from each species. Under high stringency conditions, all probes were specific to species possessing the same genome or genomes.Key words: rDNA, rice, genome-specific, dot blots.

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