Diploid ancestry and evolution of Triticum kotschyi and T. peregrinum examined using variation in repeated nucleotide sequences

Genome ◽  
1992 ◽  
Vol 35 (2) ◽  
pp. 182-191 ◽  
Author(s):  
Hong-Bin Zhang ◽  
Jan Dvořák ◽  
J. Giles Waines
Keyword(s):  
Diploid Species ◽  
Nucleotide Sequences ◽  
Gene Clone ◽  
Rrna Gene ◽  
Tetraploid Species ◽  
Genome Modification ◽  
Aegilops Sharonensis ◽  
5S Rrna Gene ◽  
Aegilops Variabilis ◽  
Allotetraploid Species

Triticum peregrinum Hackel (syn. Aegilops variabilis Eig) and T. kotschyi (Boiss.) Bowden (syn. Ae. kotschyi Boiss.) are closely related allotetraploid species. Previous research indicated that they have a pair of U genomes from diploid T. umbellulatum (Zhuk.) Hackel and a pair of S genomes from a diploid species of Triticum section Sitopsis. To reinvestigate the origin of their genomes, we identified diagnostic bands in Southern blots hybridized with 27 cloned repeated nucleotide sequences and one 5S rRNA gene clone for all diploid species of Triticum L. sensu Bowden. The presence of each diagnostic band was then determined in the two tetraploid species. One pair of the genomes in both tetraploid species was found to be virtually identical to the U genome of T. umbellulatum and the other to the S1 genome of T. longissimum (Schweif. et Muschl.) Bowden or T. sharonense (Eig) Waines &Johnson (syn. Aegilops sharonensis Eig) or the internode in the phylogenetic tree of Triticum immediately preceding the divergence of T. longissimum and T. sharonense. The source of the S genomes in T. kotschyi and T. peregrinum inferred from our data differs from that inferred from cpDNA. This indicates the need to investigate the origin of nuclear genomes with nuclear genetic markers. No evidence for an extensive modification of the S genome relative to that of T. longissimum or T. sharonense was found in either tetraploid.Key words: phylogeny, polyploids, Triticum, Aegilops, Aegilops kotschyi, Aegilops variabilis, genome origin, genome modification.

scholarly journals Microbial community in persistent apical periodontitis: a 16S rRNA gene clone library analysis

2014 ◽  
Vol 48 (8) ◽  
pp. 717-728 ◽  
Author(s):  
M. N. Zakaria ◽  
T. Takeshita ◽  
Y. Shibata ◽  
H. Maeda ◽  
N. Wada ◽  
...  
Keyword(s):  
Microbial Community ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Clone Library ◽  
Apical Periodontitis ◽  
Gene Clone ◽  
Rrna Gene ◽  
Clone Library Analysis

A natural case of RIP: degeneration of the DNA sequence in an ancestral tandem duplication

1989 ◽  
Vol 9 (10) ◽  
pp. 4416-4421
Author(s):  
W S Grayburn ◽  
E U Selker
Keyword(s):  
Dna Methylation ◽  
Tandem Duplication ◽  
De Novo ◽  
5S Rrna ◽  
Rrna Genes ◽  
Structural Basis ◽  
Rrna Gene ◽  
Oak Ridge ◽  
5S Rrna Gene ◽  
5S Rrna Genes

5S rRNA genes of Neurospora crassa are generally dispersed in the genome and are unmethylated. The xi-eta region of Oak Ridge strains represents an informative exception. Most of the cytosines in this region, which consists of a diverged tandem duplication of a 0.8-kilobase-pair segment including a 5S rRNA gene, appear to be methylated (E. U. Selker and J. N. Stevens, Proc. Natl. Acad. Sci. USA 82:8114-8118, 1985). Previous work demonstrated that the xi-eta region functions as a portable signal for de novo DNA methylation (E. U. Selker and J. N. Stevens, Mol. Cell. Biol. 7:1032-1038, 1987; E. U. Selker, B. C. Jensen, and G. A. Richardson, Science 238:48-53, 1987). To identify the structural basis of this property, we have isolated and characterized an unmethylated allele of the xi-eta region from N. crassa Abbott 4. The Abbott 4 allele includes a single 5S rRNA gene, theta, which is different from all previously identified Neurospora 5S rRNA genes. Sequence analysis suggests that the xi-eta region arose from the theta region by duplication of a 794-base-pair segment followed by 267 G.C to A.T mutations in the duplicated DNA. The distribution of these mutations is not random. We propose that the RIP process of N. crassa (E. U. Selker, E. B. Cambareri, B. C. Jensen, and K. R. Haack, Cell 51:741-752, 1987; E. U. Selker, and P. W. Garrett, Proc. Natl. Acad. Sci. USA 85:6870-6874, 1988; E. B. Cambareri, B. C. Jensen, E. Schabtach, and E. U. Selker, Science 244:1571-1575, 1989) is responsible for the numerous transition mutations and DNA methylation in the xi-eta region. A long homopurine-homopyrimidine stretch immediately following the duplicated segment is 9 base pairs longer in the Oak Ridge allele than in the Abbott 4 allele. Triplex DNA, known to occur in homopurine-homopyrimidine sequences, may have mediated the tandem duplication.

A new species of trypanosome, Trypanosoma desterrensis sp. n., isolated from South American bats

Parasitology ◽  
2003 ◽  
Vol 127 (3) ◽  
pp. 265-271 ◽  
Author(s):  
E. C. GRISARD ◽  
N. R. STURM ◽  
D. A. CAMPBELL
Keyword(s):  
New Species ◽  
Dna Sequence ◽  
Sequence Data ◽  
Rrna Gene ◽  
South American ◽  
Sequence Variability ◽  
Dna Sequence Data ◽  
Hybridization Probes ◽  
5S Rrna Gene ◽  
A New Species

Trypanosomes isolated from South American bats include the human pathogen Trypanosoma cruzi. Other Trypanosoma spp. that have been found exclusively in bats are not well characterized at the DNA sequence level and we have therefore used the SL RNA gene to differentiate and characterize kinetoplastids isolated from bats in South America. A Trypanosoma sp. isolated from bats in southern Brazil was compared with the geographically diverse isolates T. cruzi marinkellei, T. vespertilionis, and T. dionisii. Analysis of the SL RNA gene repeats revealed size and sequence variability among these bat trypanosomes. We have developed hybridization probes to separate these bat isolates and have analysed the DNA sequence data to estimate their relatedness. A new species, Trypanosoma desterrensis sp. n., is proposed, for which a 5S rRNA gene was also found within the SL RNA repeat.

DNA methylation inhibits transcription by RNA polymerase III of a tRNA gene, but not of a 5S rRNA gene

FEBS Letters ◽  
1990 ◽  
Vol 269 (2) ◽  
pp. 358-362 ◽  
Author(s):  
Daniel Besser ◽  
Frank Götz ◽  
Kai Schulze-Forster ◽  
Herbert Wagner ◽  
Hans Kröger ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Rna Polymerase ◽  
Trna Gene ◽  
Rna Polymerase Iii ◽  
5S Rrna ◽  
Rrna Gene ◽  
Polymerase Iii ◽  
5S Rrna Gene

scholarly journals Interploid Hybridizations in Ornamental Cherries Using Prunus maackii

2012 ◽  
Vol 30 (2) ◽  
pp. 89-92
Author(s):  
Margaret Pooler ◽  
Hongmei Ma ◽  
David Kidwell-Slak
Keyword(s):  
United States ◽  
Tissue Culture ◽  
Cold Hardiness ◽  
Diploid Species ◽  
Pest Resistance ◽  
The United States ◽  
Tetraploid Species ◽  
Genetic Base ◽  
Flowering Cherry ◽  
New Cultivars

The United States National Arboretum has an ongoing flowering cherry (Prunus) breeding program aimed at broadening the genetic base of cultivated ornamental cherries by developing new cultivars with disease and pest resistance, tolerance to environmental stresses, and superior ornamental characteristics. Interploid crosses, specifically 2X × 4X, in ornamental Prunus would be beneficial in breeding because they could allow introgression of traits not available in the diploid germplasm (pest resistance, cold hardiness), and could result in the creation of seedless triploids that would not set nuisance fruit and possibly have extended bloom durations. This report documents successful hybridization of P. maackii (Manchurian or Amur cherry), a tetraploid species, with P. campanulata, P. ‘Umineko’, and P. maximowiczii, all diploid species. Chromosomes of one of these resulting triploid hybrids were successfully doubled using oryzalin in tissue culture to create a hexaploid plant.

scholarly journals Isolation of Polymer-Degrading Bacteria and Characterization of the Hindgut Bacterial Community from the Detritus-Feeding Larvae of Tipula abdominalis (Diptera: Tipulidae)

2007 ◽  
Vol 73 (17) ◽  
pp. 5683-5686 ◽  
Author(s):  
Dana M. Cook ◽  
Emily DeCrescenzo Henriksen ◽  
Rima Upchurch ◽  
Joy B. Doran Peterson
Keyword(s):  
Microbial Community ◽  
Initial Study ◽  
Gene Clone ◽  
Rrna Gene ◽  
Bacterial Isolates ◽  
Future Studies ◽  
Degrading Bacteria ◽  
Novel Bacteria ◽  
Tipula Abdominalis

ABSTRACT The Tipula abdominalis larval hindgut microbial community presumably facilitates digestion of the lignocellulosic diet. The microbial community was investigated through characterization of bacterial isolates and analysis of 16S rRNA gene clone libraries. This initial study revealed novel bacteria and provides a framework for future studies of this symbiosis.

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