Characterization of genome in tetraploid StY species of Elymus (Triticeae: Poaceae) using sequential FISH and GISH

Genome ◽  
2017 ◽  
Vol 60 (8) ◽  
pp. 679-685 ◽  
Author(s):  
Ruijuan Liu ◽  
Richard R.-C. Wang ◽  
Feng Yu ◽  
Xingwang Lu ◽  
Quanwen Dou

Genomes of ten species of Elymus, either presumed or known as tetraploid StY, were characterized using fluorescence in situ hybridization (FISH) and genomic in situ hybridization (GISH). These tetraploid species could be grouped into three categories. Type I included StY genome reported species—Roegneria pendulina, R. nutans, R. glaberrima, R. ciliaris, and Elymus nevskii, and StY genome presumed species—R. sinica, R. breviglumis, and R. dura, whose genome could be separated into two sets based on different GISH intensities. Type I genome constitution was deemed as putative StY. The St genome were mainly characterized with intense hybridization with pAs1, fewer AAG sites, and linked distribution of 5S rDNA and 18S-26S rDNA, while the Y genome with less intense hybridization with pAs1, more varied AAG sites, and isolated distribution of 5S rDNA and 18S-26S rDNA. Nevertheless, further genomic variations were detected among the different StY species. Type II included E. alashanicus, whose genome could be easily separated based on GISH pattern. FISH and GISH patterns suggested that E. alashanicus comprised a modified St genome and an unknown genome. Type III included E. longearistatus, whose genome could not be separated by GISH and was designated as StlYl. Notably, a close relationship between Sl and Yl genomes was observed.

Genome ◽  
1996 ◽  
Vol 39 (3) ◽  
pp. 535-542 ◽  
Author(s):  
Concha Linares ◽  
Juan González ◽  
Esther Ferrer ◽  
Araceli Fominaya

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.


Genome ◽  
1999 ◽  
Vol 42 (1) ◽  
pp. 52-59 ◽  
Author(s):  
S N Raina ◽  
Y Mukai

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.


Genome ◽  
1995 ◽  
Vol 38 (6) ◽  
pp. 1061-1069 ◽  
Author(s):  
A. Cuadrado ◽  
N. Jouve ◽  
C. Ceoloni

The molecular characterization of heterochromatin in six lines of rye has been performed using fluorescence in situ hybridization (FISH). The highly repetitive rye DNA sequences pSc 119.2, pSc74, and pSc34, and the probes pTa71 and pSc794 containing the 25S–5.8S–18S rDNA (NOR) and the 5S rDNA multigene families, respectively, were used. This allowed the individual identification of all seven rye chromosomes and most chromosome arms in all lines. All varieties showed similar but not identical patterns. A standard in situ hybridization map was constructed following the nomenclature system recommended for C-bands. All FISH sites observed appeared to correspond well with C-band locations, but not all C-banding sites coincided with hybridization sites of the repetitive DNA probes used. Quantitative and qualitative differences between different varieties were found for in situ hybridization response at corresponding sites. Variation between plants and even between homologous chromosomes of the same plant was found in open-pollinated lines. In inbred lines, the in situ pattern of the homologues was practically identical and no variation between plants was detected. The observed quantitative and qualitative differences are consistent with a corresponding variation for C-bands detected both within and between cultivars.Key words: fluorescence in situ hybridization, repetitive DNA, rye, Secale cereale, polymorphism.


Genome ◽  
1999 ◽  
Vol 42 (5) ◽  
pp. 1008-1012 ◽  
Author(s):  
F Fontana ◽  
M Lanfredi ◽  
M Chicca ◽  
L Congiu ◽  
J Tagliavini ◽  
...  

The genes for 28S and 5S rDNA were physically mapped on the chromosomes of two sturgeon species, the sterlet (Acipenser ruthenus, 2n = 118 ± 4) and the Adriatic sturgeon (Acipenser naccarii, 2n = 248 ± 4) by fluorescent in situ hybridization. In the sterlet, the 28S rDNA was located on six chromosomes, four of which actively transcribed, while in the Adriatic sturgeon the 28S rDNA was located on a chromosome number ranging from 10 to 12, eight of which actively transcribed. The 5S rDNA was physically mapped on two chromosomes in the sterlet and on four in the Adriatic sturgeon. A more detailed characterization of the latter karyotype was obtained during this study. All these data are discussed in connection with the ploidy relationships among sturgeon species.Key words: karyotype, ploidy, FISH, 28S and 5S rDNA.


Genome ◽  
1996 ◽  
Vol 39 (6) ◽  
pp. 1150-1158 ◽  
Author(s):  
Ekatherina D. Badaeva ◽  
Bernd Friebe ◽  
Bikram S. Gill

The distribution of the 5S and 18S–5.8S–26S (18S–26S) ribosomal RNA (rRNA) gene families on chromosomes of all diploid Aegilops species was studied by in situ hybridization with pTa71 (18S–26S rDNA) and pTa794 (5S rDNA) DNA clones. One major 18S–26S rDNA locus was found in the nucleolus organizer region (NOR) of each of the species Aegilops tauschii and Aegilops uniaristata and two loci were detected in the remaining species. In addition to major NORs, from one to nine minor loci were observed; their numbers and chromosomal locations were species-specific. Some minor loci were polymorphic, whereas others were conserved. One or two 5S rDNA loci were observed in the short arms of the chromosomes of groups 1 and 5 of all diploid Aegilops species except Ae. uniaristata, where one 5S rDNA site was located in the distal part of the long arm of chromosome 1N. The 5S rDNA loci were not associated with NORs; however, the relative positions of two ribosomal RNA gene families were diagnostic for chromosomes of homoeologous groups 1, 5, and 6. Implications of these results for establishing phylogenetic relationships of diploid Aegilops species and mechanisms of genome differentiation are discussed. Key words : wheat, Triticum, Aegilops, 5S rRNA, 18S–26S rRNA, in situ hybridization, evolution.


Genome ◽  
1993 ◽  
Vol 36 (1) ◽  
pp. 77-86 ◽  
Author(s):  
Nam-Soo Kim ◽  
J. Kuspira ◽  
K. Armstrong ◽  
R. Bhambhani

In situ hybridization with [3H]dCTP labelled pScT7 (5S rDNA) and pTa80 (18S + 26S rDNA) indicated that both hybridized to the terminal regions of two pairs of chromosomes in Triticum monococcum. When the hybridization was performed with a mixture of both probes, only two pairs of chromosome arms were labelled, which suggested that the loci of both genes were located in juxtaposition to one another. Both probes labelled one pair of sites more heavily than the other. Southern analysis of 5S with BamHI-digested DNA from 12 accessions of T. monococcum (including T. urartu) produced two superimposed ladders of approximate sizes of 500 and 330 bp, which differ from T. aestivum in which 500- and 420-bp ladders were found. The 500-bp ladder is derived from chromosome 5A (5SDna-A2) and the 330-bp ladder from chromosome 1A (5SDna-A1). The recognition site for SstI was present in the long spacer region but absent in the short spacer as in T. aestivum; however, unlike T. aestivum, there were HaeIII (GGCC) and HindIII (AAGCTT) recognition sites in the short spacer region. The TaqI recognition sites (TCGA) in the long and short spacer regions are probably more highly methylated in T. monococcum than in T. aestivum. The results have implications regarding the evolutionary changes that occurred in the A genome of the hexaploid compared with the diploid.Key words: Triticum monococcum, 5S rDNA, 18S + 26S rDNA, in situ hybridization, Southern hybridization, restriction fragments, methylation.


1990 ◽  
Vol 85 (6) ◽  
pp. 569-575 ◽  
Author(s):  
Frank Speleman ◽  
Bart Van der Auwera ◽  
Kathelijne Mangelschots ◽  
Miet Vercruyssen ◽  
Ton Raap ◽  
...  

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