scholarly journals Divergence, differential methylation and interspersion of melon satellite DNA sequences

1981 ◽  
Vol 195 (3) ◽  
pp. 723-734 ◽  
Author(s):  
R Shmookler Reis ◽  
J N Timmis ◽  
J Ingle
Keyword(s):  
Dna Sequences ◽  
Satellite Dna ◽  
Dna Analysis ◽  
Buoyant Density ◽  
Sequence Divergence ◽  
Main Band ◽  
Repeat Array ◽  
Tandem Repeat Sequences ◽  
Tandem Arrays

Melon (Cucumis melo) satellite DNA consists of two components, Q and S, each with a buoyant density in CsCl of 1.707 g/ml, but differing by 9 degrees C in “melting” temperature. These physical properties appear to be in contradiction, since both depend on G + C content. In order to resolve this anomaly, base compositions were directly determined for isolated fractions. the low-“melting” component S contains 41.8% G + C, with 6% of C present as 5-methylcytosine, whereas Q DNA contains 54% G + C, with 41% of C methylated. Analyses of restriction site loss agreed well with the direct determinations of methylation and divergence, and indicated some clustering of methylated sites in Q DNA. Analysis of restricted main-band DNA by hydridization with RNA complementary to Q satellite DNA (“Southern transfer”) showed satellite Q tandem arrays interspersed in DNA of main-band density. Sequence divergence and extent of methylation did not appear to depend on whether a repeat array was present as satellite or interspersed in main-band DNA. Hydridization in situ indicated considerable heterogeneity in the genomic proportion of the Q-DNA sequences in melon fruit nuclei, implying over- and under-representation consistent with extensive unequal recombination in satellite Q tandem arrays. The cucumber, Cucumis sativus, contains less than 8% as much Q-homologous DNA per genome as the melon, suggesting rapid evolutionary gain or loss of these tandem repeat sequences.

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.

Satellite DNA in Plants: More than Just Rubbish

2015 ◽  
Vol 146 (2) ◽  
pp. 153-170 ◽  
Author(s):  
Manuel A. Garrido-Ramos
Keyword(s):  
Dna Sequences ◽  
Satellite Dna ◽  
Dna Repeats ◽  
Satellite Dnas ◽  
Factors Affecting ◽  
Functional Roles ◽  
Tandem Repeat Sequences ◽  
Satellite Repeats ◽  
History Of ◽  
Main Components

For decades, satellite DNAs have been the hidden part of genomes. Initially considered as junk DNA, there is currently an increasing appreciation of the functional significance of satellite DNA repeats and of their sequences. Satellite DNA families accumulate in the heterochromatin in different parts of the eukaryotic chromosomes, mainly in pericentromeric and subtelomeric regions, but they also span the functional centromere. Tandem repeat sequences may spread from subtelomeric to interstitial loci, leading to the formation of chromosome-specific loci or to the accumulation in equilocal sites in different chromosomes. They also appear as the main components of the heterochromatin in the sex-specific region of sex chromosomes. Satellite DNA, required for chromosome organization, also plays a role in pairing and segregation. Some satellite repeats are transcribed and can participate in the formation and maintenance of heterochromatin structure and in the modulation of gene expression. In addition to the identification of the different satellite DNA families, their characteristics and location, we are interested in determining their impact on the genomes, by identifying the mechanisms leading to their appearance and amplification as well as in understanding how they change over time, the factors affecting these changes, and the influence exerted by the evolutionary history of the organisms. On the other hand, satellite DNA sequences are rapidly evolving sequences that may cause reproductive barriers between organisms and promote speciation. The accumulation of experimental data collected in recent years and the emergence of new approaches based on next-generation sequencing and high-throughput genome analysis are opening new perspectives that are changing our understanding of satellite DNA. This review examines recent data to provide a timely update on the overall information gathered about this part of the genome, focusing on the advances in the knowledge of its origin, its evolution, and its potential functional roles.

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.

scholarly journals Satellite DNA Sequences in the Red Kangaroo (Macropus rufus)

1982 ◽  
Vol 35 (3) ◽  
pp. 313 ◽  
Author(s):  
A Elizur ◽  
E S Dennis ◽  
WJ Peacock
Keyword(s):  
Dna Sequences ◽  
Satellite Dna ◽  
Complex Pattern ◽  
Equilibrium Density ◽  
Density Gradients ◽  
Hoechst 33258 ◽  
Main Band ◽  
Red Kangaroo ◽  
Macropus Rufus

There is a complex pattern of satellite DNA sequences in M. rufus which are revealed by addition of Ag+ or dye (Hoechst 33258) to the DNA in CS2S04 or CsCI equilibrium density gradients. Six satellite DNA fractions have been isolated; these have buoyant densities in neutral CsCI of 1� 692, 1� 704, 1� 705, 1� 707 (two), 1� 710 and 1� 712 gjml compared with 1� 696 g/ml for the main band DNA. Each satellite accounts for 1-3 % of the DNA of the genome.

Differential sensitivity of some human alphoid and classical satellite DNA regions from lymphocyte chromosomes to in situ exonuclease III digestion

Genome ◽  
1996 ◽  
Vol 39 (6) ◽  
pp. 1210-1213
Author(s):  
José Luis Fernández ◽  
Carmen López-Fernández ◽  
Jaime Gosálvez ◽  
Vicente Goyanes
Keyword(s):  
Dna Sequences ◽  
Satellite Dna ◽  
Fluorescent In Situ Hybridization ◽  
Human Lymphocytes ◽  
Differential Sensitivity ◽  
Satellite Dnas ◽  
Exonuclease Iii ◽  
Human Cytogenetics ◽  
Structural Differences

Fluorescent in situ hybridization of alphoid and classical satellite III DNA sequences was performed on fixed chromosomes from human lymphocytes that were previously digested in situ with exonuclease III to produce single-stranded DNA motifs. Digital image analysis showed that while labeled alphoid satellite DNAs produced signals of similar strength to thermally denatured chromosomes, those of classical satellite III DNAs of chromosomes 9 and Yq were around 50% weaker. This result shows a differential sensitivity of these satellite DNA regions to in situ exonuclease III digestion and suggests structural differences in the higher-order organization of both subchromosomal constitutive heterochromatic regions. Key words : alphoid sequences, classical satellite, exonuclease III, FISH, human cytogenetics, satellite DNA.

Sau3A in situ digestion of human chromosome 3 pericentromeric heterochromatin. I. Differential digestion of α-satellite and satellite 1 DNA sequences

Genome ◽  
2001 ◽  
Vol 44 (1) ◽  
pp. 120-127 ◽  
Author(s):  
I Buño ◽  
J L Fernández ◽  
C López-Fernández ◽  
J L Díez-Martín ◽  
J Gosálvez
Keyword(s):  
Human Chromosome ◽  
Dna Sequences ◽  
Satellite Dna ◽  
Domain Size ◽  
Pericentromeric Heterochromatin ◽  
Chromosome 3 ◽  
Human Chromosome 3 ◽  
Domain 3 ◽  
Differential Digestion

In situ digestion with the restriction endonuclease (RE) Sau3A (Sau3A REISD) uncovers a polymorphism for the pericentromeric heterochromatin of human chromosome 3, which can be positively stained (3+) or not (3–), and has proven useful to differentiate donor and recipient cells after sex-matched bone marrow transplantation and to analyze the so-called hemopoietic chimerism. The aim of the present investigation was to obtain insight into the molecular basis of such polymorphism to optimize its use for chimerism quantification using methodological approaches other than REISD. To this end, fluorescence in situ hybridization (FISH) assays using probes for the satellite DNA sequences that mainly constitute chromosome 3 pericentromeric heterochromatin (α-satellite and satellite 1 DNA) were performed on control and Sau3A-digested chromosomes. The results obtained suggest that chromosome 3 α-satellite DNA is digested in all individuals studied, irrespective of the karyotype obtained by Sau3A REISD (3++, 3+–, 3--), and thus it does not seem to be involved in the polymorphism uncovered by Sau3A on this chromosome. Satellite 1 DNA is not digested in any case, and shows a polymorphism for its domain size, which correlates with the polymorphism uncovered by Sau3A in such a way that 3+ chromosomes show a large domain (3L) and 3– chromosomes show a small domain (3S). It seems, therefore, that the cause of the polymorphism uncovered by Sau3A on the pericentromeric region of chromosome 3 is a difference in the size of the satellite 1 DNA domain. Small satellite 1 DNA domains fall under the resolution level of REISD technique and are identified as 3–.Key words: heterochromatin, α-satellite DNA, classical satellite DNA, satellite 1 DNA, restriction endonucleases, FISH.

The genomics of long tandem arrays of satellite DNA in the human genome

Genome ◽  
1989 ◽  
Vol 31 (2) ◽  
pp. 737-744 ◽  
Author(s):  
Huntington F. Willard
Keyword(s):  
Human Genome ◽  
Dna Sequences ◽  
Satellite Dna ◽  
Hierarchical Organization ◽  
Chromosomal Mapping ◽  
Genetic Linkage Analysis ◽  
Evolutionary Analysis ◽  
Range Restriction ◽  
And Behavior

At least 10% of DNA in the human genome consists of long arrays of repeated sequences, arranged in tandem head-to-tail arrays in a number of discrete, highly localized chromosomal regions. Different families of these so-called "satellite DNA" sequences have been defined, organized in diverged subsets on different chromosomes. The molecular, cytogenetic, and evolutionary analysis of the hierarchical organization of such sequences in the human and other complex genomes encompasses a variety of approaches, including chromosomal mapping, in situ hybridization, genetic linkage analysis, long-range restriction mapping, and DNA sequencing. Investigation of the organization of satellite arrays constitutes a necessary first step towards eventual elucidation of the origin, evolution, and maintenance of these sequences and their contribution to the structure and behavior of human chromosomes.Key words: human genome, satellite DNA, chromosomes, genome analysis.

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