Physical mapping of the 5S rDNA gene complex in rice (Oryza sativa)

Genome ◽  
1993 ◽  
Vol 36 (4) ◽  
pp. 658-661 ◽  
Author(s):  
Y. C. Song ◽  
J. P. Gustafson

This study was designed to use biotin labelling in situ hybridization to physically map the 5S rDNA genes to a chromosome arm location in rice. Chromosome preparations were made using an improved protoplast technique, which resulted in more mitotic cells with less overlying cytoplasmic and cellular debris. Cells in which both chromatids were labelled were observed. The hybridization detection level for the 5S rDNA gene complex was 17.22%. The results established that the 5S rDNA gene complex of rice is located at the end of the short arm of chromosome 9 in rice cultivar IR36. The similarities and differences of the 5S rDNA gene complex location between rice and other cereals and advantages of in situ hybridization for physical mapping are discussed.Key words: biotin labelling, in situ hybridization.

Genome ◽  
1993 ◽  
Vol 36 (3) ◽  
pp. 517-523 ◽  
Author(s):  
I. J. Leitch ◽  
J. S. Heslop-Harrison

The 5S rDNA sequences have been mapped on four pairs of barley (Hordeum vulgare L.) chromosomes using in situ hybridization and barley monotelotrisomic lines. The 5S rDNA sequences are located, genetically and physically, on the short arm of chromosome 1 (7I) and the long arms of chromosomes 2 (2I) and 3 (3I). The 5S rDNA sequence is also located on the physically long arm of chromosome 4 (4I). Only one site on chromosome 2(2I) has previously been reported. The characteristic locations of the 5S rDNA sequences make them useful as molecular markers to identify each barley chromosome. The physical position of the low-copy α-amylase-2 gene was determined using in situ hybridization; the location of this gene on the long arm of chromosome 1 (7I) was confirmed by reprobing the same preparation with the 5S rDNA probe. The results show that there is a discrepancy between the physical and genetic position of the α-amylase-2 gene.Key words: genetic mapping, physical mapping, barley, mapping, 5S DNA, α-amylase, in situ hybridization.


Genome ◽  
2002 ◽  
Vol 45 (1) ◽  
pp. 189-197 ◽  
Author(s):  
Piotr A Ziolkowski ◽  
Jan Sadowski

To improve resolution of physical mapping on Brassica chromosomes, we have chosen the pachytene stage of meiosis where incompletely condensed bivalents are much longer than their counterparts at mitotic metaphase. Mapping with 5S and 45S rDNA sequences demonstrated the advantage of pachytene chromosomes in efficient physical mapping and confirmed the presence of a novel 5S rDNA locus in Brassica oleracea, initially identified by genetic mapping using restriction fragment length polymorphism (RFLP). Fluorescence in situ hybridization (FISH) analysis visualized the presence of the third 5S rDNA locus on the long arm of chromosome C2 and confirmed the earlier reports of two 45S rDNA loci in the B. oleracea genome. FISH mapping of low-copy sequences from the Arabidopsis thaliana bacterial artificial chromosome (BAC) clones on the B. oleracea chromosomes confirmed the expectation of efficient and precise physical mapping of meiotic bivalents based on data available from A. thaliana and indicated conserved organization of these two BAC sequences on two B. oleracea chromosomes. Based on the heterologous in situ hybridization with BACs and their mapping applied to long pachytene bivalents, a new approach in comparative analysis of Brassica and A. thaliana genomes is discussed.Key words: Brassicaceae, pachytene chromosomes, FISH, rDNA, BACs.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Liuyang Fu ◽  
Qian Wang ◽  
Lina Li ◽  
Tao Lang ◽  
Junjia Guo ◽  
...  

Abstract Background Chromosomal variants play important roles in crop breeding and genetic research. The development of single-stranded oligonucleotide (oligo) probes simplifies the process of fluorescence in situ hybridization (FISH) and facilitates chromosomal identification in many species. Genome sequencing provides rich resources for the development of oligo probes. However, little progress has been made in peanut due to the lack of efficient chromosomal markers. Until now, the identification of chromosomal variants in peanut has remained a challenge. Results A total of 114 new oligo probes were developed based on the genome-wide tandem repeats (TRs) identified from the reference sequences of the peanut variety Tifrunner (AABB, 2n = 4x = 40) and the diploid species Arachis ipaensis (BB, 2n = 2x = 20). These oligo probes were classified into 28 types based on their positions and overlapping signals in chromosomes. For each type, a representative oligo was selected and modified with green fluorescein 6-carboxyfluorescein (FAM) or red fluorescein 6-carboxytetramethylrhodamine (TAMRA). Two cocktails, Multiplex #3 and Multiplex #4, were developed by pooling the fluorophore conjugated probes. Multiplex #3 included FAM-modified oligo TIF-439, oligo TIF-185-1, oligo TIF-134-3 and oligo TIF-165. Multiplex #4 included TAMRA-modified oligo Ipa-1162, oligo Ipa-1137, oligo DP-1 and oligo DP-5. Each cocktail enabled the establishment of a genome map-based karyotype after sequential FISH/genomic in situ hybridization (GISH) and in silico mapping. Furthermore, we identified 14 chromosomal variants of the peanut induced by radiation exposure. A total of 28 representative probes were further chromosomally mapped onto the new karyotype. Among the probes, eight were mapped in the secondary constrictions, intercalary and terminal regions; four were B genome-specific; one was chromosome-specific; and the remaining 15 were extensively mapped in the pericentric regions of the chromosomes. Conclusions The development of new oligo probes provides an effective set of tools which can be used to distinguish the various chromosomes of the peanut. Physical mapping by FISH reveals the genomic organization of repetitive oligos in peanut chromosomes. A genome map-based karyotype was established and used for the identification of chromosome variations in peanut following comparisons with their reference sequence positions.


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.


Genome ◽  
2004 ◽  
Vol 47 (1) ◽  
pp. 179-189 ◽  
Author(s):  
J L Stephens ◽  
S E Brown ◽  
N L.V Lapitan ◽  
D L Knudson

The primary objective of this study was to elucidate gene organization and to integrate the genetic linkage map for barley (Hordeum vulgare L.) with a physical map using ultrasensitive fluorescence in situ hybridization (FISH) techniques for detecting signals from restriction fragment length polymorphism (RFLP) clones. In the process, a single landmark plasmid, p18S5Shor, was constructed that identified and oriented all seven of the chromosome pairs. Plasmid p18S5Shor was used in all hybridizations. Fourteen cDNA probes selected from the linkage map for barley H. vulgare 'Steptoe' × H. vulgare 'Morex' (Kleinhofs et al. 1993) were mapped using an indirect tyramide signal amplification technique and assigned to a physical location on one or more chromosomes. The haploid barley genome is large and a complete physical map of the genome is not yet available; however, it was possible to integrate the linkage map and the physical locations of these cDNAs. An estimate of the ratio of base pairs to centimorgans was an average of 1.5 Mb/cM in the distal portions of the chromosome arms and 89 Mb/cM near the centromere. Furthermore, while it appears that the current linkage maps are well covered with markers along the length of each arm, the physical map showed that there are large areas of the genome that have yet to be mapped.Key words: Hordeum vulgare, barley, physical mapping, FISH, cDNA, genetics, linkage, chromosome, BACs.


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.


Genes ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 375 ◽  
Author(s):  
Xiaomei Luo ◽  
Juncheng Liu

We report the cytogenetic map for a collection of species in the Oleaceae, and test similarities among the karyotypes relative to their known species phylogeny. The oligonucleotides 5S ribosomal DNA (rDNA), (AGGGTTT)3, and (TTG)6 were used as fluorescence in situ hybridization (FISH) probes to locate the corresponding chromosomes in three Oleaceae genera: Fraxinus pennsylvanica, Syringa oblata, Ligustrum lucidum, and Ligustrum × vicaryi. Forty-six small chromosomes were identified in four species. (AGGGTTT)3 signals were observed on almost all chromosome ends of four species, but (AGGGTTT)3 played no role in distinguishing the chromosomes but displayed intact chromosomes and could thus be used as a guide for finding chromosome counts. (TTG)6 and 5S rDNA signals discerned several chromosomes located at subterminal or central regions. Based on the similarity of the signal pattern (mainly in number and location and less in intensity) of the four species, the variations in the 5S rDNA and (TTG)6 distribution can be ordered as L. lucidum < L. × vicaryi < F. pennsylvanica < S. oblata. Variations have observed in the three genera. The molecular cytogenetic data presented here might serve as a starting point for further larger-scale elucidation of the structure of the Oleaceae genome, and comparison with the known phylogeny of Oleaceae family.


Sign in / Sign up

Export Citation Format

Share Document