The Nor-D3 locus of Triticum tauschii: natural variation and genetic linkage to markers in chromosome 5

Genome ◽  
1991 ◽  
Vol 34 (3) ◽  
pp. 387-395 ◽  
Author(s):  
E. S. Lagudah ◽  
R. Appels ◽  
D. McNeil
Keyword(s):  
Ribosomal Rna ◽  
Intergenic Spacer ◽  
D Genome ◽  
Triticum Tauschii ◽  
Intergenic Spacer Region ◽  
Grain Softness ◽  
High Level ◽  
Rna Genes ◽  
Rdna Polymorphism ◽  
Grain Softness Protein

Variation in the intergenic spacer region of the ribosomal RNA genes (located at the Nor locus) was assayed in a collection of 411 accessions of Triticum tauschii from Turkey, USSR, Iran, Afghanisan, Pakistan, and China. Twenty rDNA genotypes were identified and it was demonstrated that T. tauschii accessions from the USSR and Iran have the highest diversity at the Nor locus. At least four of the rDNA genotypes were demonstrated to be alleles of a single major locus, in segregating F2 progeny analyses. The TaqI restriction fragment associated with rDNA genotype 7 was shown to be the same as the Nor-D3a allele present in all bread wheats (based on chromosome location and length of the intergenic spacer region). This genotype was significantly associated with T. t. ssp. strangulata, previously argued to be the donor of the D genome to hexaploid wheat. The Nor locus showed a high level of recombination with the 5SDna-2 locus, which was also located on chromosome 5D. The Nor locus is placed distal to the 5SDna-2 locus but proximal to the grain softness protein gene (XGsp) on the short arm of chromosome 5D.Key words: D genome, Nor-D3, rDNA polymorphism, chromosomal location.

DNA fingerprinting of tabanids (Diptera: Tabanidae) and their respective egg masses using PCR – restriction fragment profiling

2004 ◽  
Vol 136 (5) ◽  
pp. 605-619 ◽  
Author(s):  
M. Iranpour ◽  
A.M. Schurko ◽  
G.R. Klassen ◽  
T.D. Galloway
Keyword(s):  
Restriction Fragment ◽  
Ribosomal Rna ◽  
Intergenic Spacer ◽  
Interspecific Variation ◽  
Egg Masses ◽  
Polymerase Chain ◽  
High Level ◽  
Rna Genes ◽  
Profiling Analysis ◽  
Respective Species

AbstractPolymerase chain reaction and subsequent restriction fragment profiling analysis were used to associate collected tabanid egg masses with their respective species of adult horse flies and deer flies (Diptera: Tabanidae) in Manitoba, Canada. The ribosomal DNA (rDNA) intergenic spacer between the 28S and 18S ribosomal RNA genes was used successfully to differentiate 34 species of adult tabanids representing five genera: Atylotus (1 sp.), Chrysops (10 spp.), Haematopota (1 sp.), Hybomitra (17 spp.), and Tabanus (5 spp.). rDNA was a suitable molecular target for identifying tabanid species because of the high level of interspecific variation when comparing fragment profiles among different species, and the corresponding minimal intraspecific variation among individuals of the same species. Restriction fragment profiles from 56 field-collected tabanid egg masses were compared with those previously obtained from adults of known species. Egg masses of five species were identified: Hybomitra lasiophthalma (Macquart), Hybomitra nitidifrons nuda (McDunnough), Chrysops aestuans van der Wulp, Chrysops excitans Walker, and Chrysops mitis Osten Sacken. We also provide physical descriptions of these tabanid egg masses along with pictures.

Molecular evolution of the intergenic spacer in the nuclear ribosomal RNA genes of Cucurbitaceae

1993 ◽  
Vol 36 (2) ◽  
pp. 144-152 ◽  
Author(s):  
Klaus King ◽  
Ramon A. Torres ◽  
Ulrike Zentgraf ◽  
Vera Hemleben
Keyword(s):  
Molecular Evolution ◽  
Ribosomal Rna ◽  
Intergenic Spacer ◽  
Ribosomal Rna Genes ◽  
Rna Genes

Species and Genus Specificity of the Intergenic Spacer (IGS) in the Ribosomal RNA Genes of Cucurbitaceae

1989 ◽  
Vol 44 (11-12) ◽  
pp. 1029-1034 ◽  
Author(s):  
R. A. Torres ◽  
U. Zentgraf ◽  
V. Hemleben
Keyword(s):  
Cucumis Sativus ◽  
Ribosomal Rna ◽  
Ribosomal Dna ◽  
Cucumis Melo ◽  
Intergenic Spacer ◽  
Specific Pattern ◽  
Cross Hybridization ◽  
Cucumis Species ◽  
External Transcribed Spacer ◽  
Rna Genes

Abstract The use of intergenic spacer (IGS) fragments of plant ribosomal DNA (rDNA) for the differ­ entiation between genera and species is tested by cross-hybridization experiments with different IGS probes of two Cucurbitaceae, Cucurbita pepo (zucchini) and Cucumis sativus (cucum ber). Hybridization with cloned fragments of different parts of the IGS of ribosomal DNA exhibit a different degree of conservation within and between the Cucurbitaceae genera. In general, Cucur­ bita species seem to be closer related to each other than the Cucumis species. A repetitive element of the external transcribed spacer (ETS) shows a more genus-specific pattern, reacting only with the respective genera; the region preceding the ETS is conserved between the Cucurbita species but also cross-hybridizes weakly with the Cucumis species. AGC-rich element of the Cucumis sativus IGS (“Cfo-cluster”) is present in small amounts in Cucumis melo (melon) and even less represented in other genera of the Cucurbitaceae.

scholarly journals Comparative mitogenomics of the zoonotic parasite Echinostoma revolutum resolves taxonomic relationships within the ‘E. revolutum’ species group and the Echinostomata (Platyhelminthes: Digenea)

Parasitology ◽  
2020 ◽  
Vol 147 (5) ◽  
pp. 566-576 ◽  
Author(s):  
Thanh Hoa Le ◽  
Linh Thi Khanh Pham ◽  
Huong Thi Thanh Doan ◽  
Xuyen Thi Kim Le ◽  
Weerachai Saijuntha ◽  
...  
Keyword(s):  
Ribosomal Rna ◽  
Species Group ◽  
Coding Region ◽  
Protein Coding ◽  
Repeat Units ◽  
Short Repeat ◽  
Echinostoma Revolutum ◽  
Zoonotic Parasite ◽  
High Level ◽  
Rna Genes

AbstractThe complete mitochondrial sequence of 17,030 bp was obtained from Echinostoma revolutum and characterized with those of previously reported members of the superfamily Echinostomatoidea, i.e. six echinostomatids, one echinochasmid, five fasciolids, one himasthlid, and two cyclocoelids. Relationship within suborders and between superfamilies, such as Echinostomata, Pronocephalata, Troglotremata, Opisthorchiata, and Xiphiditata, are also considered. It contained 12 protein-coding, two ribosomal RNA, 22 transfer RNA genes and a tandem repetitive consisting non-coding region (NCR). The gene order, one way-positive transcription, the absence of atp8 and the overlapped region by 40 bp between nad4L and nad4 genes were similar as in common trematodes. The NCR located between tRNAGlu (trnE) and cox3 contained 11 long (LRUs) and short repeat units (SRUs) (seven LRUs of 317 bp, four SRUs of 207 bp each), and an internal spacer sequence between LRU7 and SRU4 specifying high-level polymorphism. Special DHU-arm missing tRNAs for Serine were found for both tRNAS1(AGN) and tRNAS2(UCN). Echinostoma revolutum indicated the lowest divergence rate to E. miyagawai and the highest to Tracheophilus cymbius and Echinochasmus japonicus. The usage of ATG/GTG start and TAG/TAA stop codons, the AT composition bias, the negative AT-skewness, and the most for Phe/Leu/Val and the least for Arg/Asn/Asp codons were noted. Topology indicated the monophyletic position of E. revolutum to E. miyagawai. Monophyly of Echinostomatidae and Fasciolidae was clearly solved with respect to Echinochasmidae, Himasthlidae, and Cyclocoelidae which were rendered paraphyletic in the suborder Echinostomata.

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