The molecular identification of the midget chromosome from the rye genome

Genome ◽  
1994 ◽  
Vol 37 (6) ◽  
pp. 1056-1061 ◽  
Author(s):  
M. G. Francki ◽  
P. Langridge

The diminutive "midget" chromosome is found in plants containing a wheat nuclear genome with a substituted rye cytoplasm. This cytoplasmic substituted line arose during successive backcrossing of a wheat/rye amphiploid to wheat as the recurrent male parent. Southern and in situ hybridization with a dispersed repeat sequence specific for rye, R173, indicates that the midget chromosome originates from within the rye genome. Various DNA markers previously mapped to group 1 chromosomes of wheat and barley were used to trace the origin of the midget chromosome from within the rye genome. Ten short arm and 36 long arm probes were used and one marker was identified, which hybridizes to the midget chromosome and maps to the proximal region of the long arm of chromosome 1R. An additional marker was generated from a genomic library of the line containing the midget chromosome. This also maps to the long arm of 1R. The results indicate that the midget chromosome contains a small segment of the long arm of chromosome 1R.Key words: midget chromosome, RFLP markers, chromosome 1R, repeated DNA sequence.

Genome ◽  
1995 ◽  
Vol 38 (4) ◽  
pp. 803-808 ◽  
Author(s):  
J. A. Anderson ◽  
S. S. Maan

Triticum longissimum cytoplasm is incompatible with the T. turgidum nuclear genome. Two nuclear genes, scs and Vi, derived from the nuclear genome of T. timopheevii and by a spontaneous mutation, respectively, restore nuclear–cytoplasmic compatibility, normal plant vigor, and male fertility in these alloplasmic genotypes. The objectives of this study were (i) to determine the chromosomal locations of scs and Vi; (ii) to identify DNA markers for scs and Vi; and (iii) to determine the interactions involving the dosage of scs and Vi. Two populations segregating for scs and Vi were produced and scored for seedling vigor (indicating presence of scs) and degree of self-fertility (indicating presence of Vi). Four RFLP markers were mapped near scs. Aneuploid analysis revealed that these markers, and hence the scs gene, are located on the long arm of chromosome 1A. Four RFLP markers were mapped near Vi on 1BS. Results indicated that other factors may be inhibiting the expression of Vi. We determined the dosage of scs and Vi in both populations with the aid of the linked RFLP markers. Individuals with two versus one dose of scs had reduced self-fertility, while individuals with two versus one dose of Vi had similar self-fertility.Key words: scs, Vi, Triticum, nucleocytoplasmic compatibility, RFLP.


Genetics ◽  
2001 ◽  
Vol 157 (4) ◽  
pp. 1735-1747 ◽  
Author(s):  
Devinder Sandhu ◽  
Julie A Champoux ◽  
Svetlana N Bondareva ◽  
Kulvinder S Gill

AbstractThe short arm of Triticeae homeologous group 1 chromosomes is known to contain many agronomically important genes. The objectives of this study were to physically localize gene-containing regions of the group 1 short arm, enrich these regions with markers, and study the distribution of genes and recombination. We focused on the major gene-rich region (“1S0.8 region”) and identified 75 useful genes along with 93 RFLP markers by comparing 35 different maps of Poaceae species. The RFLP markers were tested by gel blot DNA analysis of wheat group 1 nullisomic-tetrasomic lines, ditelosomic lines, and four single-break deletion lines for chromosome arm 1BS. Seventy-three of the 93 markers mapped to group 1 and detected 91 loci on chromosome 1B. Fifty-one of these markers mapped to two major gene-rich regions physically encompassing 14% of the short arm. Forty-one marker loci mapped to the 1S0.8 region and 10 to 1S0.5 region. Two cDNA markers mapped in the centromeric region and the remaining 24 loci were on the long arm. About 82% of short arm recombination was observed in the 1S0.8 region and 17% in the 1S0.5 region. Less than 1% recombination was observed for the remaining 85% of the physical arm length.


Genome ◽  
2002 ◽  
Vol 45 (4) ◽  
pp. 777-783 ◽  
Author(s):  
Masahiro Hizume ◽  
Fukashi Shibata ◽  
Ayako Matsumoto ◽  
Yukie Maruyama ◽  
Eiji Hayashi ◽  
...  

Repetitive DNA was cloned from HindIII-digested genomic DNA of Larix leptolepis. The repetitive DNA was about 170 bp long, had an AT content of 67%, and was organized tandemly in the genome. Using fluorescence in situ hybridization and subsequent DAPI banding, the repetitive DNA was localized in DAPI bands at the proximal region of one arm of chromosomes in L. leptolepis and Larix chinensis. Southern blot hybridization to genomic DNA of seven species and five varieties probed with cloned repetitive DNA showed that the repetitive DNA family was present in a tandem organization in genomes of all Larix taxa examined. In addition to the 170-bp sequence, a 220-bp sequence belonging to the same DNA family was also present in 10 taxa. The 220-bp repeat unit was a partial duplication of the 170-bp repeat unit. The 220-bp repeat unit was more abundant in L. chinensis and Larix potaninii var. macrocarpa than in other taxa. The repetitive DNA composed 2.0–3.4% of the genome in most taxa and 0.3 and 0.5% of the genome in L. chinensis and L. potaninii var. macrocarpa, respectively. The unique distribution of the 220-bp repeat unit in Larix indicates the close relationship of these two species. In the family Pinaceae, the LPD (Larix proximal DAPI band specific repeat sequence family) family sequence is widely distributed, but their amount is very small except in the genus Larix. The abundant LPD family in Larix will occur after its speciation.Key words: AT-rich tandem repetitive DNA, fluorescence in situ hybridization, Larix, proximal DAPI band.


Genome ◽  
1998 ◽  
Vol 41 (4) ◽  
pp. 527-534 ◽  
Author(s):  
Andreas Katsiotis ◽  
Marianna Hagidimitriou ◽  
Alexandra Douka ◽  
Polydefkis Hatzopoulos

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.


Development ◽  
1994 ◽  
Vol 120 (3) ◽  
pp. 637-647
Author(s):  
R.P. Tucker ◽  
J. Spring ◽  
S. Baumgartner ◽  
D. Martin ◽  
C. Hagios ◽  
...  

Previous studies have shown that several forms of the glycoprotein tenascin are present in the embryonic extracellular matrix. These forms are the result of alternative splicing, which generates tenascin variants with different numbers of fibronectin type III repeats. We have used degenerate primers and PCR to isolate a novel tenascin exon from an avian genomic library. Genomic clones contained a sequence encoding a fibronectin type III repeat that corresponds to repeat ‘C’ from the variable domain of human tenascin. To demonstrate that tenascin containing repeat ‘C’ is actually synthesized by avian cells, a monospecific antiserum was raised against a repeat ‘C’ fusion protein. This antiserum recognized a novel high-molecular-weight variant on immunoblots of tenascin isolated from chicken embryo fibroblast-conditioned medium, and stained tendons on frozen sections of chicken embryos. A cDNA probe specific for mRNA encoding repeat ‘C’ was used for in situ hybridization. This probe hybridized in a subset of the embryonic tissues labelled with a universal tenascin probe, including tendons, ligaments and mesenchyme at sites of epithelial-mesenchymal interactions. Finally, we provide evidence that additional fibronectin type III repeats, one corresponding to a recently discovered human repeat as well as one entirely novel sequence, also exists in chicken tenascin mRNA. These data indicate that tenascin is present in the embryonic matrix in a multitude of forms and that these forms have distinctive distributions that may reflect more than one function for tenascin in development.


Genome ◽  
2001 ◽  
Vol 44 (3) ◽  
pp. 401-412 ◽  
Author(s):  
X -F. Ma ◽  
K Ross ◽  
J P Gustafson

Using wheat ditelosomic lines and in situ hybridization of biotin-labelled DNA probes, 18 restriction fragment length polymorphism (RFLP) markers were physically located on homoeologous groups 1 and 3 chromosomes of wheat. Most of the markers hybridized to chromosome arms in a physical order concordant with the genetic maps. A majority of the markers studied were clustered in non-C-banded, distal euchromatic areas, indicating the presence of recombination hot spots and cold spots in those regions. However, on 1BS the markers were well dispersed, which could be due to the abundance of heterochromatin throughout the arm. An inversion between Xpsr653 and Xpsr953 was observed on 1AL. One new Xpsr688 locus, approximately 20–26% from the centromere, was found on 1AS and 1BS. The physical location of Xpsr170 on group 3 chromosomes probably represents an alternative to the loci on the genetic map. Finally, Xpsr313 was mapped to two physical loci on 1DL. Five markers were located to bins consistent with the deletion-based physical maps.Key words: wheat, physical mapping, in situ hybridization.


Cells ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 286 ◽  
Author(s):  
Damien Jeandard ◽  
Anna Smirnova ◽  
Ivan Tarassov ◽  
Eric Barrey ◽  
Alexandre Smirnov ◽  
...  

Mitochondria harbor their own genetic system, yet critically depend on the import of a number of nuclear-encoded macromolecules to ensure their expression. In all eukaryotes, selected non-coding RNAs produced from the nuclear genome are partially redirected into the mitochondria, where they participate in gene expression. Therefore, the mitochondrial RNome represents an intricate mixture of the intrinsic transcriptome and the extrinsic RNA importome. In this review, we summarize and critically analyze data on the nuclear-encoded transcripts detected in human mitochondria and outline the proposed molecular mechanisms of their mitochondrial import. Special attention is given to the various experimental approaches used to study the mitochondrial RNome, including some recently developed genome-wide and in situ techniques.


2020 ◽  
Vol 21 (20) ◽  
pp. 7690
Author(s):  
Tigran Harutyunyan ◽  
Ahmed Al-Rikabi ◽  
Anzhela Sargsyan ◽  
Galina Hovhannisyan ◽  
Rouben Aroutiounian ◽  
...  

Translocation of mtDNA in the nuclear genome is an ongoing process that contributes to the development of pathological conditions in humans. However, the causal factors of this biological phenomenon in human cells are poorly studied. Here we analyzed mtDNA insertions in the nuclear genome of human lymphocytes after in vitro treatment with doxorubicin (DOX) using a fluorescence in situ hybridization (FISH) technique. The number of mtDNA insertions positively correlated with the number of DOX-induced micronuclei, suggesting that DOX-induced chromosome breaks contribute to insertion events. Analysis of the odds ratios (OR) revealed that DOX at concentrations of 0.025 and 0.035 µg/mL significantly increases the rate of mtDNA insertions (OR: 3.53 (95% CI: 1.42–8.76, p < 0.05) and 3.02 (95% CI: 1.19–7.62, p < 0.05), respectively). Analysis of the distribution of mtDNA insertions in the genome revealed that DOX-induced mtDNA insertions are more frequent in larger chromosomes, which are more prone to the damaging action of DOX. Overall, our data suggest that DOX-induced chromosome damage can be a causal factor for insertions of mtDNA in the nuclear genome of human lymphocytes. It can be assumed that the impact of a large number of external and internal mutagenic factors contributes significantly to the origin and amount of mtDNA in nuclear genomes.


Genome ◽  
2000 ◽  
Vol 43 (1) ◽  
pp. 185-190 ◽  
Author(s):  
J Perez ◽  
P Moran ◽  
E Garcia-Vazquez

This work describes the isolation, characterization, and physical location of the methionine tRNA in the genome of Atlantic salmon (Salmo salar L.) and brown trout (Salmo trutta L.). An Atlantic salmon genomic library was screened using a tRNAMet probe from Xenopus laevis. Two cosmid clones containing the Atlantic salmon tRNAMet gene were isolated, subcloned and sequenced. The tRNAMet was mapped to metaphase chromosomes by fluorescence in situ hybridization (FISH). Chromosomal data indicated that the tDNA of methionine is tandemly repeated in a single locus in both species. Analysis of genomic DNA by Southern hybridization confirmed the tandem organization of this gene. Key words: cosmids, cloning, in situ hybridization, tRNAMet.


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