scholarly journals cT-DNA in Linaria vulgaris L. is multicopy, inverted and homogenized

2019 ◽  
Author(s):  
Ivan A. Vladimirov ◽  
Olga A. Pavlova ◽  
Dmitrii E. Polev ◽  
Denis I. Bogomaz
Keyword(s):  
Dna Sequences ◽  
Copy Number ◽  
Digital Pcr ◽  
Dna Repeats ◽  
Linaria Vulgaris ◽  
Plant Genomes ◽  
Duplication Events ◽  
Dna Elements ◽  
Long Range Pcr ◽  
Ct Dna

AbstractThe phenomenon of evolutionary fixation of agrobacterial sequences (cT-DNA or cellular transferred DNA) in plant genomes is well known in nature. It was previously considered, that all of cT-DNA-containing species, except Linaria vulgaris, have multiple inverted cT-DNA repeats. Deep studying of general features of cT-DNA brings us closer to understanding the causes and mechanisms of its fixation in plants genomes. We combined multiple long-range PCR with genome walking for studying extended structure of cT-DNA. Using digital PCR method, we estimated copy number of cT-DNA elements. NGS with low covering allows us to develop a set of microsatellite markers, also used for copy number estimation. According to new data, cT-DNA elements in L. vulgaris form an inverted complex repeat of two simple direct repeats. After cT-DNA integration, cT-DNA sequence duplication events took place at least two times. The phenomenon of concerted evolution of cT-DNA sequences as well as some details of this process have been shown for the first time.We have shown, that L. vulgaris, as well as other cT-DNA containing species, has inverted structure of repeats. This fact indicates possible existence of some general causes and mechanisms of cT-DNA fixation in plant genomes during evolution.

Highly Condensed Potato Pericentromeric Heterochromatin Contains rDNA-Related Tandem Repeats

Genetics ◽  
2002 ◽  
Vol 162 (3) ◽  
pp. 1435-1444 ◽  
Author(s):  
Robert M Stupar ◽  
Junqi Song ◽  
Ahmet L Tek ◽  
Zhukuan Cheng ◽  
Fenggao Dong ◽  
...  
Keyword(s):  
Repetitive Dna ◽  
Dna Sequences ◽  
Tandem Repeats ◽  
Intergenic Spacer ◽  
Pericentromeric Heterochromatin ◽  
Dna Repeats ◽  
Solanum Bulbocastanum ◽  
Origin And Evolution ◽  
Potato Genome ◽  
Dna Elements

Abstract The heterochromatin in eukaryotic genomes represents gene-poor regions and contains highly repetitive DNA sequences. The origin and evolution of DNA sequences in the heterochromatic regions are poorly understood. Here we report a unique class of pericentromeric heterochromatin consisting of DNA sequences highly homologous to the intergenic spacer (IGS) of the 18S•25S ribosomal RNA genes in potato. A 5.9-kb tandem repeat, named 2D8, was isolated from a diploid potato species Solanum bulbocastanum. Sequence analysis indicates that the 2D8 repeat is related to the IGS of potato rDNA. This repeat is associated with highly condensed pericentromeric heterochromatin at several hemizygous loci. The 2D8 repeat is highly variable in structure and copy number throughout the Solanum genus, suggesting that it is evolutionarily dynamic. Additional IGS-related repetitive DNA elements were also identified in the potato genome. The possible mechanism of the origin and evolution of the IGS-related repeats is discussed. We demonstrate that potato serves as an interesting model for studying repetitive DNA families because it is propagated vegetatively, thus minimizing the meiotic mechanisms that can remove novel DNA repeats.

DNA methylation in satellite repeats disorders

2019 ◽  
Vol 63 (6) ◽  
pp. 757-771 ◽  
Author(s):  
Claire Francastel ◽  
Frédérique Magdinier
Keyword(s):  
Dna Methylation ◽  
Human Genome ◽  
Repetitive Dna ◽  
Dna Sequences ◽  
Satellite Repeats ◽  
Tremendous Progress ◽  
Genes Encoding ◽  
Dna Elements ◽  
Near Future

Abstract Despite the tremendous progress made in recent years in assembling the human genome, tandemly repeated DNA elements remain poorly characterized. These sequences account for the vast majority of methylated sites in the human genome and their methylated state is necessary for this repetitive DNA to function properly and to maintain genome integrity. Furthermore, recent advances highlight the emerging role of these sequences in regulating the functions of the human genome and its variability during evolution, among individuals, or in disease susceptibility. In addition, a number of inherited rare diseases are directly linked to the alteration of some of these repetitive DNA sequences, either through changes in the organization or size of the tandem repeat arrays or through mutations in genes encoding chromatin modifiers involved in the epigenetic regulation of these elements. Although largely overlooked so far in the functional annotation of the human genome, satellite elements play key roles in its architectural and topological organization. This includes functions as boundary elements delimitating functional domains or assembly of repressive nuclear compartments, with local or distal impact on gene expression. Thus, the consideration of satellite repeats organization and their associated epigenetic landmarks, including DNA methylation (DNAme), will become unavoidable in the near future to fully decipher human phenotypes and associated diseases.

scholarly journals Telomeric DNA sequences in beetle taxa vary with species richness

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Daniela Prušáková ◽  
Vratislav Peska ◽  
Stano Pekár ◽  
Michal Bubeník ◽  
Lukáš Čížek ◽  
...  
Keyword(s):  
Species Richness ◽  
Dna Sequences ◽  
Genome Instability ◽  
Telomeric Sequence ◽  
Dna Repeats ◽  
Telomeric Dna ◽  
Common Pattern ◽  
Telomeric Sequences ◽  
Genomic Changes ◽  
Protective Structures

AbstractTelomeres are protective structures at the ends of eukaryotic chromosomes, and disruption of their nucleoprotein composition usually results in genome instability and cell death. Telomeric DNA sequences have generally been found to be exceptionally conserved in evolution, and the most common pattern of telomeric sequences across eukaryotes is (TxAyGz)n maintained by telomerase. However, telomerase-added DNA repeats in some insect taxa frequently vary, show unusual features, and can even be absent. It has been speculated about factors that might allow frequent changes in telomere composition in Insecta. Coleoptera (beetles) is the largest of all insect orders and based on previously available data, it seemed that the telomeric sequence of beetles varies to a great extent. We performed an extensive mapping of the (TTAGG)n sequence, the ancestral telomeric sequence in Insects, across the main branches of Coleoptera. Our study indicates that the (TTAGG)n sequence has been repeatedly or completely lost in more than half of the tested beetle superfamilies. Although the exact telomeric motif in most of the (TTAGG)n-negative beetles is unknown, we found that the (TTAGG)n sequence has been replaced by two alternative telomeric motifs, the (TCAGG)n and (TTAGGG)n, in at least three superfamilies of Coleoptera. The diversity of the telomeric motifs was positively related to the species richness of taxa, regardless of the age of the taxa. The presence/absence of the (TTAGG)n sequence highly varied within the Curculionoidea, Chrysomeloidea, and Staphylinoidea, which are the three most diverse superfamilies within Metazoa. Our data supports the hypothesis that telomere dysfunctions can initiate rapid genomic changes that lead to reproductive isolation and speciation.

Micronuclear DNA sequences from Tetrahymena do not confer mitotic stability on ARS plasmids in Saccharomyces

Genome ◽  
1988 ◽  
Vol 30 (5) ◽  
pp. 690-696 ◽  
Author(s):  
Wendy H. Horsfall ◽  
Ronald E. Pearlman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Sequences ◽  
Copy Number ◽  
Tetrahymena Thermophila ◽  
Assay System ◽  
Mitotic Stability ◽  
Yeast Saccharomyces Cerevisiae ◽  
Genomic Libraries ◽  
Ade2 Gene

Genomic libraries containing micronuclear DNA sequences from Tetrahymena thermophila have been constructed in a vector containing ARS1, SUP11, and ura3 sequences from the yeast Saccharomyces cerevisiae. When transformed into a strain of S. cerevisiae carrying a suppressible ochre mutation in the ade2 gene, viable transformants are obtained only if the transforming plasmid is maintained at a copy number of one or two per cell. Mitotic segregation of the plasmid is easily assessed in a colour assay of transformants. Using this assay system, we showed that micronuclear DNA from Tetrahymena does not contain sequences that confer mitotic stability on yeast ARS-containing plasmids; i.e., sequences that function analogously to yeast centromere sequences. One transformant was analyzed that carries Tetrahymena sequences that maintain the copy number of the ARS plasmid at one or two per cell. However, these sequences do not confer mitotic stability on the transformants and they confer a phenotype in this assay similar to that of the REP3 gene of the yeast 2 μm plasmid.Key words: mitotic stability, centromere, Tetrahymena, Saccharomyces.

Characterization of High-Copy-Number Retrotransposons From the Large Genomes of the Louisiana Iris Species and Their Use as Molecular Markers

Genetics ◽  
2003 ◽  
Vol 164 (2) ◽  
pp. 685-697 ◽  
Author(s):  
Edward K Kentner ◽  
Michael L Arnold ◽  
Susan R Wessler
Keyword(s):  
Molecular Markers ◽  
Copy Number ◽  
High Copy Number ◽  
Marker System ◽  
Transposon Display ◽  
Plant Genomes ◽  
Large Plant ◽  
Backcross Hybrids ◽  
Abundance And Distribution

Abstract The Louisiana iris species Iris brevicaulis and I. fulva are morphologically and karyotypically distinct yet frequently hybridize in nature. A group of high-copy-number TY3/gypsy-like retrotransposons was characterized from these species and used to develop molecular markers that take advantage of the abundance and distribution of these elements in the large iris genome. The copy number of these IRRE elements (for iris retroelement), is ∼1 × 105, accounting for ∼6–10% of the ∼10,000-Mb haploid Louisiana iris genome. IRRE elements are transcriptionally active in I. brevicaulis and I. fulva and their F1 and backcross hybrids. The LTRs of the elements are more variable than the coding domains and can be used to define several distinct IRRE subfamilies. Transposon display or S-SAP markers specific to two of these subfamilies have been developed and are highly polymorphic among wild-collected individuals of each species. As IRRE elements are present in each of 11 iris species tested, the marker system has the potential to provide valuable comparative data on the dynamics of retrotransposition in large plant genomes.

Distribution, expression and germ line transmission of exogenous DNA sequences following microinjection into Xenopus laevis eggs

Development ◽  
1987 ◽  
Vol 99 (1) ◽  
pp. 15-23
Author(s):  
L.D. Etkin ◽  
B. Pearman
Keyword(s):  
Xenopus Laevis ◽  
Dna Sequences ◽  
Copy Number ◽  
Germ Line ◽  
Gene Promoter ◽  
Early Gene ◽  
Mosaic Pattern ◽  
Exogenous Dna ◽  
Gene Coding ◽  
Germ Line Transmission

We analysed the fate, expression and germ line transmission of exogenous DNA which was microinjected into fertilized eggs of Xenopus laevis. DNA was injected into fertilized eggs within 1 h following fertilization. The injected DNA was dispersed around the site of injection and became localized to cleavage nuclei by stage 6. Injected DNA persisted in the tissues of 6- to 8-month-old frogs and exhibited a mosaic pattern of distribution with regard to the presence or absence and copy number between different tissues. We detected the exogenous DNA sequences in 60% of injected frogs. Restriction digestion analysis of this DNA suggested that it is not rearranged and was organized as head-to-tail multimers. The copy number varied from 2 to 30 copies/cell in various tissues of the same frog. Plasmid pSV2CAT which contains the prokaryotic gene coding for chloramphenicol acetyl transferase (CAT) enzyme linked to the SV40 early gene promoter was expressed in 50% of the animals containing the gene. The pattern of expression, however, varied between different animals and could not be correlated with copy number. We also showed that the exogenous DNA sequences were transmitted through the male germ line and that each offspring contained the gene integrated into a different region of the genome.

scholarly journals Accurate measurement of transgene copy number in crop plants using droplet digital PCR

2017 ◽  
Vol 90 (5) ◽  
pp. 1014-1025 ◽  
Author(s):  
Ray Collier ◽  
Kasturi Dasgupta ◽  
Yan-Ping Xing ◽  
Bryan Tarape Hernandez ◽  
Min Shao ◽  
...  
Keyword(s):  
Copy Number ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Crop Plants ◽  
Transgene Copy Number

Variable copy number DNA sequences in rice

1987 ◽  
Vol 210 (3) ◽  
pp. 373-380 ◽  
Author(s):  
Shoshi Kikuchi ◽  
Fumio Takaiwa ◽  
Kiyoharu Oono
Keyword(s):  
Dna Sequences ◽  
Copy Number
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