Differential behavior of Solanum brevidens ribosomal DNA loci in a somatic hybrid and its progeny with potato

Genome ◽  
1998 ◽  
Vol 41 (3) ◽  
pp. 435-439 ◽  
Author(s):  
J Mitchell McGrath ◽  
John P Helgeson
Keyword(s):  
In Situ Hybridization ◽  
Somatic Hybrid ◽  
Specific Marker ◽  
Parent Species ◽  
Solanum Brevidens ◽  
Backcross Generation ◽  
Diploid Parent ◽  
Somatic Fusion ◽  
Rdna Loci

Fluorescence in situ hybridization was used to characterize loci encoding ribosomal RNA (rDNA) among parents and progeny of a somatic fusion between tetraploid Solanum tuberosum (potato) and diploid Solanum brevidens. As expected, four major sites of hybridization to rDNA loci were evident in the tetraploid parent species, two in the diploid parent species, and six in the hexaploid somatic fusion plant. Two of the loci in the somatic fusion plant showed differential signals relative to the other four, which were interpreted as a delayed condensation of sites harboring the rDNA loci. This delayed condensation was heritable to the first backcross generation of the somatic hybrid crossed with potato. In the second backcross generation, differential condensation was not evident. However, a heterochromatic isochromosome was observed whose presence was correlated with a S. brevidens specific marker linked with the rDNA locus. It is suggested that the S. brevidens rDNA loci are preferentially affected in the somatic hybrid and its progeny, and that the delayed condensation may have contributed to the formation of the isochromosome.Key words: introgression, recombination, isochromosome, in situ hybridization.

scholarly journals Fluorescence in situ hybridization of potato somatohaploids and their somatic hybrid donors using two Solanum brevidens specific sequences

1998 ◽  
Vol 7 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Veli-Matti Rokka ◽  
Nora L. V. Lapitan ◽  
Dennis L. Knudson ◽  
Eija Pehu
Keyword(s):  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
Repetitive Dna ◽  
Digital Imaging ◽  
Somatic Hybrid ◽  
Fluorescent Dyes ◽  
Somatic Hybrids ◽  
Solanum Brevidens ◽  
Specific Sequences

Two Solanum brevidens specific repetitive DNA clones (pSB1 and pSB7) were used simultaneously as probes in fluorescence in situ hybridization (FISH) for cytological studies of somatohaploids and their somatic hybrid donors. pSB1 was labelled with digoxigenin-11-dUTP and pSB7 was labelled with biotin-14-dATP and they were detected with reporter molecules conjugated to fluorescent dyes using digital imaging. The tandemly repeated sequences hybridized mostly near the telomeres of the chromosomes of S. brevidens. Using these two probes, it was possible to identify chromosomes containing repetitive DNA of S. brevidens both in the somatic hybrids between S. brevidens and S. tuberosum, and somatohaploids derived from the somatic hybrids. These cytological analyses showed that for the largest part genomes of the hexaploid somatic hybrids and their anther-derived triploid somatohaploids were composed of the genome of S. brevidens.

The use of double fluorescence in situ hybridization to physically map the positions of 5S rDNA genes in relation to the chromosomal location of 18S–5.8S–26S rDNA and a C genome specific DNA sequence in the genus Avena

Genome ◽  
1996 ◽  
Vol 39 (3) ◽  
pp. 535-542 ◽  
Author(s):  
Concha Linares ◽  
Juan González ◽  
Esther Ferrer ◽  
Araceli Fominaya
Keyword(s):  
In Situ Hybridization ◽  
Dna Sequence ◽  
Diploid Species ◽  
5S Rdna ◽  
Rdna Genes ◽  
26S Rdna ◽  
A Genome ◽  
Rdna Loci ◽  
C Genome

A physical map of the locations of the 5S rDNA genes and their relative positions with respect to 18S–5.8S–26S rDNA genes and a C genome specific repetitive DNA sequence was produced for the chromosomes of diploid, tetraploid, and hexaploid oat species using in situ hybridization. The A genome diploid species showed two pairs of rDNA loci and two pairs of 5S loci located on both arms of one pair of satellited chromosomes. The C genome diploid species showed two major pairs and one minor pair of rDNA loci. One pair of subtelocentric chromosomes carried rDNA and 5S loci physically separated on the long arm. The tetraploid species (AACC genomes) arising from these diploid ancestors showed two pairs of rDNA loci and three pairs of 5S loci. Two pairs of rDNA loci and 2 pairs of 5S loci were arranged as in the A genome diploid species. The third pair of 5S loci was located on one pair of A–C translocated chromosomes using simultaneous in situ hybridization with 5S rDNA genes and a C genome specific repetitive DNA sequence. The hexaploid species (AACCDD genomes) showed three pairs of rDNA loci and six pairs of 5S loci. One pair of 5S loci was located on each of two pairs of C–A/D translocated chromosomes. Comparative studies of the physical arrangement of rDNA and 5S loci in polyploid oats and the putative A and C genome progenitor species suggests that A genome diploid species could be the donor of both A and D genomes of polyploid oats. Key words : oats, 5S rDNA genes, 18S–5.8S–26S rDNA genes, C genome specific repetitive DNA sequence, in situ hybridization, genome evolution.

Detection of a variable number of 18S-5.8S-26S and 5S ribosomal DNA loci by fluorescent in situ hybridization in diploid and tetraploid Arachis species

Genome ◽  
1999 ◽  
Vol 42 (1) ◽  
pp. 52-59 ◽  
Author(s):  
S N Raina ◽  
Y Mukai
Keyword(s):  
In Situ Hybridization ◽  
5S Rdna ◽  
Gene Families ◽  
Ribosomal Gene ◽  
Rrna Genes ◽  
Tetraploid Species ◽  
Arachis Species ◽  
26S Rdna ◽  
Rdna Loci

In order to obtain new information on the genome organization of Arachis ribosomal DNA, more particularly among A. hypogaea and its close relatives, the distribution of the 18S-5.8S-26S and 5S ribosomal RNA gene families on the chromosomes of 21 diploid and tetraploid Arachis species, selected from six of nine taxonomic sections, was analyzed by in situ hybridization with pTa71 (18S-5.8S-26S rDNA) and pTa794 (5S rDNA) clones. Two major 18S-5.8S-26S rDNA loci with intense signals were found in the nucleolus organizer regions (NOR) of each of the diploid and tetraploid species. In addition to extended signals at major NORs, two to six medium and (or) minute-sized signals were also observed. Variability in the number, size, and location of 18S-5.8S-26S sites could generally distinguish species within the same genome as well as between species with different genomes. The use of double fluorescence in situ hybridization enabled us to locate the positions of 5S rRNA genes in relation to the chromosomal location of 18S-5.8S-26S rRNA genes in Arachis chromosomes which were difficult to karyotype. Two or four 5S rDNA loci and 18S-5.8S-26S rDNA loci were generally located on different chromosomes. The tandemly repeated 5S rDNA sites were diagnostic for T and C genomes. In one species, each of B and Am genomes, the two ribosomal gene families were observed to occur at the same locus. Barring A. ipaensis and A. valida, all the diploid species had characteristic centromeric bands in all the 20 chromosomes. In tetraploid species A. hypogaea and A. monticola only 20 out of 40 chromosomes showed centromeric bands. Comparative studies of distribution of the two ribosomal gene families, and occurrence of centromeric bands in only 20 chromosomes of the tetraploid species suggests that A. villosa and A. ipaensis are the diploid progenitors of A. hypogaea and A. monticola. This study excludes A. batizocoi as the B genome donor species for A. hypogaea and A. monticola.Key words: Arachis species, 5S rRNA, 18S-5.8S-26S rRNA, in situ hybridization, evolution.

Chromosomal localization and characterization of rDNA loci in the Brassica A and C genomes

Genome ◽  
1997 ◽  
Vol 40 (4) ◽  
pp. 582-587 ◽  
Author(s):  
R. J. Snowdon ◽  
W. Köhler ◽  
A. Köhler
Keyword(s):  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
Ribosomal Dna ◽  
Diploid Species ◽  
Rdna Locus ◽  
Chromosome Morphology ◽  
Rdna Site ◽  
A Genome ◽  
Rdna Loci

Using fluorescence in situ hybridization, we located ribosomal DNA loci on prometaphase chromosomes of the diploid species Brassica rapa and Brassica oleracea and their amphidiploid Brassica napus. Based on comparisons of chromosome morphology and hybridization patterns, we characterized the individual B. napus rDNA loci according to their presumed origins in the Brassica A and C genomes. As reported in other studies, the sum of rDNA loci observed on B. rapa (AA genome) and B. oleracea (CC genome) chromosomes was one greater than the total number of loci seen in their amphidiploid B. napus (AACC). Evidence is presented that this reduction in B. napus rDNA locus number results from the loss of the smallest A genome rDNA site in the amphidiploid.Key words: Brassica, fluorescence in situ hybridization, ribosomal DNA, rDNA.

Recombination of Solanum brevidens chromosomes in the second backcross generation from a somatic hybrid with S. tuberosum

1994 ◽  
Vol 88 (8) ◽  
pp. 917-924 ◽  
Author(s):  
J. M. McGrath ◽  
S. M. Wielgus ◽  
T. F. Uchytil ◽  
H. Kim-Lee ◽  
G. T. Haberlach ◽  
...  
Keyword(s):  
Somatic Hybrid ◽  
Solanum Brevidens ◽  
Backcross Generation

Chromosomal localization of two novel repetitive sequences isolated from the Chenopodium quinoa Willd. genome

Genome ◽  
2011 ◽  
Vol 54 (9) ◽  
pp. 710-717 ◽  
Author(s):  
B. Kolano ◽  
B.W. Gardunia ◽  
M. Michalska ◽  
A. Bonifacio ◽  
D. Fairbanks ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Repetitive Dna ◽  
Dna Sequences ◽  
Repetitive Sequences ◽  
Chenopodium Quinoa ◽  
5S Rdna ◽  
Rrna Gene ◽  
Fish Analysis ◽  
Rdna Loci

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.

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