A molecular analysis of the origin of the Crepis capillaris B chromosome

1994 ◽  
Vol 107 (3) ◽  
pp. 703-708 ◽  
Author(s):  
M. Jamilena ◽  
C. Ruiz Rejon ◽  
M. Ruiz Rejon

The origin of the B chromosome of Crepis capillaris has been studied by using in situ hybridization with different DNA probes. Genomic in situ hybridization (GISH) with DNA from plants with and without Bs as probes indicates that the B chromosome has many DNA sequences in common with A chromosomes, showing no region rich in B-specific sequences. Six additional DNA probes were used to test the possible origin of this B from the standard NOR chromosome (chromosome 3). In the short arm of the NOR chromosome, we detected not only 18 S + 25 S rDNA, but also 5 S rDNA and a specific repetitive sequence from the NOR chromosome (pCcH32); in the heterochromatic bands of the long arm, we found two different repetitive sequences (pCcE9 and pCcD29). In the B chromosome, however, only the 18 S + 25 S rDNA and the telomeric sequences from Arabidopsis thaliana were observed. Our in situ hybridization data with telomeric repeats indicate that the two telomeres of the B are larger than those of the A chromosomes, confirming the isochromosomal nature of this B. Hybridizations of 18 S + 25 S rDNA and telomeric repeats to blots of DNA from plants with and without Bs reveal a high homology between A and B 18 S + 25 S rDNA genes, but some sequence dissimilarities between A and B telomeres. Taken as a whole, these data indicate that the entire B of C. capillaris, although possibly having originated from the standard genome, did not derive directly from the NOR chromosome.

Genome ◽  
2011 ◽  
Vol 54 (9) ◽  
pp. 710-717 ◽  
Author(s):  
B. Kolano ◽  
B.W. Gardunia ◽  
M. Michalska ◽  
A. Bonifacio ◽  
D. Fairbanks ◽  
...  

The chromosomal organization of two novel repetitive DNA sequences isolated from the Chenopodium quinoa Willd. genome was analyzed across the genomes of selected Chenopodium species. Fluorescence in situ hybridization (FISH) analysis with the repetitive DNA clone 18–24J in the closely related allotetraploids C. quinoa and Chenopodium berlandieri Moq. (2n = 4x = 36) evidenced hybridization signals that were mainly present on 18 chromosomes; however, in the allohexaploid Chenopodium album L. (2n = 6x = 54), cross-hybridization was observed on all of the chromosomes. In situ hybridization with rRNA gene probes indicated that during the evolution of polyploidy, the chenopods lost some of their rDNA loci. Reprobing with rDNA indicated that in the subgenome labeled with 18–24J, one 35S rRNA locus and at least half of the 5S rDNA loci were present. A second analyzed sequence, 12–13P, localized exclusively in pericentromeric regions of each chromosome of C. quinoa and related species. The intensity of the FISH signals differed considerably among chromosomes. The pattern observed on C. quinoa chromosomes after FISH with 12–13P was very similar to GISH results, suggesting that the 12–13P sequence constitutes a major part of the repetitive DNA of C. quinoa.


2020 ◽  
Vol 17 (3) ◽  
pp. 393-410
Author(s):  
Hoang Thi Nhu Phuong ◽  
Huynh Thi Thu Hue ◽  
Cao Xuan Hieu

Fluorescence in situ hybridization (FISH) technique enables the direct detection of DNA sequences inintact cellular materials (e.g. individual chromosomes in metaphase spreads). This review article focuses on theapplications of FISH in genome research, including validation and correction of the genome assembly from thenext-generation sequencing (NGS) projects. DNA probes for specific DNA fragments of the assembly can beobtained from PCR amplicon or cloned products using different vector systems. Localization of these probeson their respective chromosomal regions can be visualized by FISH, providing useful information to crosscheckthe assembly data. Furthermore, the recent refinements in the FISH technology including using smartpooling scheme of differently colored DNA probes, together with consecutive FISH experiments (stripping andreprobing of the same slide) are described. These advances in multicolor FISH can provide crucial linkageinformation on association of linkage groups and assembly scaffolds, resulting in so-called cytogenetic maps.Integration of the cytogenetic maps and assembly sequences assists to resolve the chromosome-level genomeassembly and to reveal new insights in genome architecture and genome evolution. Especially, comparativechromosome painting with pooled DNA probes from one reference species can be used to investigate ancestralrelationships (chromosome homeology and rearrangements) among other not-yet-sequenced species. Inaddition, FISH using DNA probes for certain specific classes of repetitive DNA elements as well as for basicchromosome structures (e.g. centromere or telomere DNA repeats, ribosomal DNA loci) can be used to studythe genome organization and karyotype differentiation. We also discussed about limitations and futureperspectives of the FISH technology.


Genome ◽  
2001 ◽  
Vol 44 (4) ◽  
pp. 640-643 ◽  
Author(s):  
N Cuñado ◽  
E Sánchez-Morán ◽  
J Barrios ◽  
J L Santos

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.


Genome ◽  
1994 ◽  
Vol 37 (2) ◽  
pp. 320-327 ◽  
Author(s):  
D. McNeil ◽  
E. S. Lagudah ◽  
U. Hohmann ◽  
R. Appels

The sequence of a Triticum tauschii genomic clone representing a family of D-genome amplified DNA sequences, designated Dgas44, is reported. The Dgas44 sequence occurs on all chromosomes of the D genome of wheat, Triticum aestivum, and in situ hybridization revealed it to be evenly dispersed on all seven chromosome pairs. An internal HindIII fragment of Dgas44, designated Dgas44-3, defines the highly amplified region that is specific to the D genome. The polymerase chain reaction was used to amplify a 236-bp fragment within Dgas44-3 from chromosomes 1D, 2D, 3D, 4D, 5D, and 7D, and identical copies of this region of the Dgas44-3 sequence were found among the isolates from each of the chromosomes. The Dgas44-3 sequence population from specific chromosomes differed on average by 0.22% from the original Dgas44 sequence. The Dgas44 sequence was found to differentiate between the D genome present in T. aestivum, T. tauschii, hexaploid T. crassum, T. cylindricum, T. ventricosum, in which the sequence was present in a highly amplified form and T. juvenale, T. syriacum, and tetraploid T. crassum where the sequence family was difficult to detect. Another class of amplified sequences previously considered to be rye "specific." R350, was isolated from tetraploid wheat and its dispersed distribution on chromosomes was similar to the Dgas44 family in T. tauschii. In contrast with the Dgas44 sequence family, genome specificity for the remnant R350 sequence family was not evident since it was present on all wheat chromosomes.Key words: D genome, sequence amplification, in situ hybridization.


Genome ◽  
2000 ◽  
Vol 43 (6) ◽  
pp. 945-948 ◽  
Author(s):  
N Cuñado ◽  
J Barrios ◽  
J L Santos

A method of preparing two-dimensional surface spreads of plant synaptonemal complexes (SCs) associated with fluorescence in situ hybridization (FISH) has been applied to analyze the location and organization of five different highly repeated DNA sequences in rye. Our observations indicate that, depending on the type of sequence, the chromatin displays different types of organization. Telomeric sequences were seen tightly associated with the SC while other repetitive DNA sequences were found to form loops that are associated with SCs only at their bases. On the contrary, the FISH signal of a centromeric satellite had a granular appearance, reflecting that the hybridization occurs only with parts of the chromatin loops.Key words: fluorescence in situ hybridization, meiosis, repetitive DNA, rye, synaptonemal complex.


Genome ◽  
1992 ◽  
Vol 35 (5) ◽  
pp. 844-848 ◽  
Author(s):  
Joanna E. Werner ◽  
Rama S. Kota ◽  
Bikram S. Gill ◽  
T. R. Endo

The distribution of the telomeric repeats in common wheat and their role in the healing of broken ends of deleted chromosomes was studied. In situ hybridization to mitotic chromosomes was carried out using a synthetic probe that was derived from the sequence of the telomeric repeats of Arabidopsis thaliana. Sites of hybridization were visualized as double dots at both ends of each wheat chromosome. Variation in the strength of the signal that was detected among chromosome arms might be due to the variable number of telomeric repeats of each chromosome end. While signals were absent on normal chromosomes at the pericentric and intercalary regions, hybridization sites were detected at the broken chromosome ends of all deleted chromosomes included in the study. All telocentric chromosomes of multitelocentric lines of 'Chinese Spring' showed a strong signal at the centromeric region. The results suggest that a de novo chromosome healing mechanism exists in wheat involving the addition of the telomeric sequences to the ends of broken chromosome. Further evidence indicated that the healing of broken ends is probably intrinsic to replication during gametogenesis.Key words: in situ hybridization, telomeric sequences, deleted chromosomes, chromosome healing, telosome.


Genome ◽  
2003 ◽  
Vol 46 (6) ◽  
pp. 953-962 ◽  
Author(s):  
Trude Schwarzacher

In situ hybridization is a powerful and unique technique that correlates molecular information of a DNA sequence with its physical location along chromosomes and genomes. It thus provides valuable information about physical map position of sequences and often is the only means to determine abundance and distribution of repetitive sequences making up the majority of most genomes. Repeated DNA sequences, composed of units of a few to a thousand base pairs in size, occur in blocks (tandem or satellite repeats) or are dispersed (including transposable elements) throughout the genome. They are often the most variable components of a genome, often being species and, occasionally, chromosome specific. Their variability arises through amplification, diversification and dispersion, as well as homogenization and loss; there is a remarkable correlation of molecular sequence features with chromosomal organization including the length of repeat units, their higher order structures, chromosomal locations, and dispersion mechanisms. Our understanding of the structure, function, organization, and evolution of genomes and their evolving repetitive components enabled many new cytogenetic applications to both medicine and agriculture, particularly in diagnosis and plant breeding.Key words: repetitive DNA, genome organization, sequence evolution, telomere, centromere.


Sign in / Sign up

Export Citation Format

Share Document