Identification and chromosomal location of a new tandemly repeated DNA in maize

Genome ◽  
2000 ◽  
Vol 43 (1) ◽  
pp. 181-184 ◽  
Author(s):  
Chunxian Chen ◽  
Huihuang Yan ◽  
Wenxue Zhai ◽  
Lihuang Zhu ◽  
Jingsan Sun
Keyword(s):  
In Situ Hybridization ◽  
Dna Sequences ◽  
Fluorescent In Situ Hybridization ◽  
Methylation Pattern ◽  
Repeated Dna ◽  
Dna Library ◽  
New Family ◽  
Genomic Dna Library ◽  
Tandemly Repeated Dna

Two clones of a new family of tandemly repeated DNA sequences have been isolated from a maize random genomic DNA library. MR68 is 410 bp, representing a monomeric unit and MR77 is 1222 bp, containing three units. The copy number was estimated to be about 3000 per 1C maize genome. Its methylation pattern was also determined. Fluorescent in situ hybridization (FISH) indicates that the sequence is located on the subtelomeric region of the long arm of chromosomes 3 and 6, as well as on the satellite of chromosome 6. Key words: Zea mays, tandemly repeated DNA, satellite DNA, fluorescent in situ hybridization (FISH).

The molecular structure, chromosomal organization, and interspecies distribution of a family of tandemly repeated DNA sequences of Antirrhinum majus L.

Genome ◽  
1996 ◽  
Vol 39 (2) ◽  
pp. 243-248 ◽  
Author(s):  
Thomas Schmidt ◽  
Jörg Kudla
Keyword(s):  
In Situ Hybridization ◽  
Dna Sequences ◽  
Satellite Dna ◽  
Antirrhinum Majus ◽  
Repeated Dna ◽  
Satellite Dnas ◽  
Repeated Dna Sequences ◽  
The North ◽  
Tandemly Repeated Dna

Monomers of a major family of tandemly repeated DNA sequences of Antirrhinum majus have been cloned and characterized. The repeats are 163–167 bp long, contain on average 60% A + T residues, and are organized in head-to-tail orientation. According to site-specific methylation differences two subsets of repeating units can be distinguished. Fluorescent in situ hybridization revealed that the repeats are localized at centromeric regions of six of the eight chromosome pairs of A. majus with substantial differences in array size. The monomeric unit shows no homologies to other plant satellite DNAs. The repeat exists in a similar copy number and conserved size in the genomes of six European species of the genus Antirrhinum. Tandemly repeated DNA sequences with homology to the cloned monomer were also found in the North American section Saerorhinum, indicating that this satellite DNA might be of ancient origin and was probably already present in the ancestral genome of both sections. Key words : Antirrhinum majus, satellite DNA, repetitive DNA, methylation, in situ hybridization.

Genomic organization, sequence interrelationship, and physical localization using in situ hybridization of two tandemly repeated DNA sequences in the genus Olea

Genome ◽  
1998 ◽  
Vol 41 (4) ◽  
pp. 527-534 ◽  
Author(s):  
Andreas Katsiotis ◽  
Marianna Hagidimitriou ◽  
Alexandra Douka ◽  
Polydefkis Hatzopoulos
Keyword(s):  
In Situ Hybridization ◽  
Dna Sequences ◽  
Genomic Library ◽  
Repeat Sequence ◽  
Repeated Dna ◽  
Repeated Dna Sequences ◽  
Young Leaves ◽  
Partial Genomic Library ◽  
Tandemly Repeated Dna

Two tandemly repeated DNA sequences, the 81-bp family and pOS218, have been isolated from a Sau3AI Olea europaea ssp. sativa partial genomic library. Sequencing of the 81-bp element showed the monomer to be between 78 and 84 bases long and to contain 51-58% adenine and thymidine residues. Comparison between the monomers revealed heterogeneity of the sequence primary structure. The clone pOS218 is 218 bases long, and sequence comparison between the two elements revealed that an internal region of the pOS218 repeated DNA sequence had 79% homology to the 81 bp repeat sequence. A breakage-reunion mechanism, involving the CAAAA sequence, could be responsible for the derivation of pOS218 from the 81 bp family element. By using double target in situ hybridization, co-localization of the two sequences on Olea chromosomes was observed. The sequences were present at DAPI stained heterochromatic regions, as major or minor sites having a subtelomeric or interstitial location. Methylation studies using two sets of isoschizomers, Sau3AI-MboI and MspI-HpaII, demonstrated that most cytosine residues in the GATC sites and the internal cytosine in the CCGG sites of both elements were methylated in O. europaea ssp. sativa. No major difference in methylation was apparent between DNA extracted from young leaves or from callus of O. europaea ssp.sativa. Both elements are also present in Olea chrysophylla, Olea oleaster, and Olea africana, but are absent from other Oleaceae genera, including Phillyrea, Forsythia, Ligustrum, Parasyringa, and Jasminum.Key words: in situ hybridization, methylation, Oleaceae, phylogenetic relationships, repeated sequences.

Characterization of the chromosome complement of Helianthus annuus by in situ hybridization of a tandemly repeated DNA sequence

Genome ◽  
2007 ◽  
Vol 50 (5) ◽  
pp. 429-434 ◽  
Author(s):  
M. Ceccarelli ◽  
V. Sarri ◽  
L. Natali ◽  
T. Giordani ◽  
A. Cavallini ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Helianthus Annuus ◽  
Chromosome Complement ◽  
Repeated Sequence ◽  
Dna Library ◽  
Repeat Units ◽  
Genomic Dna Library ◽  
Repeated Dna Sequence ◽  
Tandemly Repeated Dna Sequence

A tandemly repeated sequence isolated from a clone (HAG004N15) of a nebulized genomic DNA library of sunflower (Helianthus annuus L., 2n = 34) was characterized and used to study the chromosome complement of sunflower. HAG004N15 repeat units (368 bp in length) were found to be highly methylated, and their copy number per haploid (1C) genome was estimated to be 7800. After in situ hybridization of HAG004N15 repeats onto chromosome spreads, signals were observed at the end of both chromosome arms in 4 pairs and at the end of only one arm in 8 other pairs. Signals were also observed at the intercalary (mostly subtelomeric) regions in all pairs, in both arms in 8 pairs, and in only one arm in the other 9 pairs. The short arm of 1 pair was labelled entirely. The chromosomal location of ribosomal DNA was also studied by hybridizing the wheat ribosomal probe pTa71. Four chromosome pairs contained ribosomal cistrons at the end of their shorter arm, but a satellite was seen in only 3 pairs. These hybridization patterns were the same in the 3 sunflower lines studied (HA89, RA20031, and HOR). The chromosomal localization of HAG004N15-related sequences allowed all of the chromosome pairs to be distinguished from each other, in spite of small size and similar morphology.

Searching for telomeric sequences in two Allium species

Genome ◽  
2001 ◽  
Vol 44 (4) ◽  
pp. 640-643 ◽  
Author(s):  
N Cuñado ◽  
E Sánchez-Morán ◽  
J Barrios ◽  
J L Santos
Keyword(s):  
In Situ Hybridization ◽  
Dna Sequences ◽  
Fluorescent In Situ Hybridization ◽  
Two Dimensional ◽  
Ltr Retrotransposons ◽  
Allium Species ◽  
Telomeric Sequences ◽  
Rdna Sequences ◽  
Dimensional Surface

Some Alliaceae species have no tandemly repeated TTTAGGG sequences. Instead, at the very end of their chromosomes, there are highly repetitive satellite and (or) rDNA sequences. These sequences apparently replace the canonical plant telomeric sequences in these species. A method of preparing two-dimensional surface spreads of plant synaptonemal complexes (SCs), combined with fluorescent in situ hybridization, has revealed that telomeric chromatin is tightly condensed at the ends of SCs in plants and animals. Using this method, we have tested the organization and location of those sequences postulated to cap the chromosomes in two species of the genus Allium: A. cepa and A. altaicum. We have also extended this study to other putative telomere candidates, such as LTR (long terminal repeat) and non-LTR retrotransposons. None of the DNA sequences analyzed showed the characteristic telomeric organization at pachytene.Key words: fluorescent in situ hybridization, meiosis, repetitive DNA, Allium, synaptonemal complex.

Characterization and chromosomal organization of satellite DNA sequences in Picea abies

Genome ◽  
2008 ◽  
Vol 51 (9) ◽  
pp. 705-713 ◽  
Author(s):  
V. Sarri ◽  
S. Minelli ◽  
F. Panara ◽  
M. Morgante ◽  
I. Jurman ◽  
...  
Keyword(s):  
Picea Abies ◽  
Dna Sequences ◽  
Satellite Dna ◽  
Sequence Similarity ◽  
Intergenic Spacer ◽  
Structural Diversity ◽  
Dna Library ◽  
Genomic Dna Library ◽  
Chromosome Regions

Three clones containing satellite DNA sequences were selected from a randomly sheared genomic DNA library of Picea abies (clones PAF1, PAG004P22F (2F), and PAG004E03C (3C)). PAF1 contained 7 repeats that were 37–55 bp in length and had 68.9%–91.9% nucleotide sequence similarity. Two 2F repeats were 305–306 bp in length and had 83% sequence similarity. Two 3C repeats were 193–226 bp in length and had a sequence similarity of 78.6%. The copy number per 1C DNA of PAF1, 2F, and 3C repeats was 2.7 × 106, 2.9 × 105, and 2.9 × 104, respectively. In situ hybridization showed centromeric localization of these sequences in two chromosome pairs with PAF1, all pairs but one with 2F, and three pairs with 3C. Moreover, PAF1 sequences hybridized at secondary constrictions in six pairs, while 2F-related sequences were found at these chromosome regions only in four pairs. These hybridization patterns allow all chromosome pairs to be distinguished. PAF1-related repeats were contained in the intergenic spacer (IGS) of ribosomal cistrons in all six nucleolar organizers of the complement, while sequences related to 2F were found on only one side of the rDNA arrays in four pairs, showing structural diversity between rDNA regions of different chromosomes.

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