Variation of molecular markers among geographically diverse accessions of Triticum tauschii

Genome ◽  
1991 ◽  
Vol 34 (3) ◽  
pp. 354-361 ◽  
Author(s):  
E. L. Lubbers ◽  
K. S. Gill ◽  
T. S. Cox ◽  
B. S. Gill
Keyword(s):  
Molecular Markers ◽  
Restriction Fragment Length Polymorphism ◽  
Genetic Variability ◽  
Length Polymorphism ◽  
Fragment Length ◽  
Caspian Sea ◽  
Germ Plasm ◽  
Fragment Length Polymorphism ◽  
The Caspian Sea ◽  
Restriction Fragment Length

Triticum tauschii (Coss.) Schmal. (genome DD), a diploid progenitor of hexaploid wheat (Triticum aestivum L.; AABBDD), grows across large areas of southwest Asia and contains more genetic variability for disease and insect resistance, isozymes, and seed storage proteins than the D genome of T. aestivum. To study patterns of variability at a large number of loci, we determined restriction fragment length polymorphism genotypes at 25 loci in a germ-plasm collection of 102 T. tauschii accessions. All accessions were homozygous at all loci, so "alleles" and "genotypes" were equivalent. Twenty loci were polymorphic, with two to six genotypes per locus and polymorphic indexes ranging from 0.06 to 0.74. Linkage disequilibrium was widespread. On the basis of Hedrick's probability of genotypic identity, botanical varieties T. t. ssp. eusquarrosa var. typica and T. t. ssp. eusquarrosa var. anathera were very similar to each other, as were T. t. ssp. strangulata and T. t. ssp. eusquarrosa var. meyeri, with a large genetic distance between these two pairs of taxonomic groups. Genetic variability for molecular markers was highest near the Caspian Sea, intermediate in Afghanistan, and lowest in Turkey and Pakistan. Genetic and geographical distances were related and generally consistent with the hypothesis that T. tauschii originated near the southern or southwestern coast of the Caspian Sea. Unique genotypes were found in most regions. The results of this study, along with data on economically relevant traits, will provide a basis for selecting breeding parents from the T. tauschii germ-plasm collection.Key words: germ plasm, Aegilops squarrosa, diversity, restriction fragment length polymorphism.

Restriction fragment length polymorphism (RFLP) analysis of three nuclear genes in rock-wallabies (Petrogale: Marsupialia: Macropodidae): a search for genic markers to identify taxa within the Petrogale lateralis-penicillata group

2001 ◽  
Vol 49 (1) ◽  
pp. 27 ◽  
Author(s):  
A. K. Loupis ◽  
M. D. B. Eldridge
Keyword(s):  
Molecular Markers ◽  
Restriction Fragment Length Polymorphism ◽  
Restriction Fragment ◽  
Length Polymorphism ◽  
Fragment Length ◽  
Fragment Length Polymorphism ◽  
Rflp Analysis ◽  
Nuclear Genes ◽  
North East ◽  
Restriction Fragment Length

Many rock-wallaby (Petrogale) species within the lateralis–penicillata complex are morphologically similar and can be distinguished only by their unique karyotypes, frustrating attempts to identify specimens in the field and in museums. As chromosome preparations are not always obtainable from specimens, additional diagnostic molecular markers are required. In this study, restriction fragment length polymorphism (RFLP) analysis of three nuclear genes was undertaken using 100 Petrogale specimens, including representatives of 12 taxa. Eleven novel diagnostic nuclear DNA markers were identified, which enabled the identification of four taxa (P. penicillata, P. purpureicollis, P. lateralis and P. inornata). No markers were found that could reliably distinguish amongst five north-east Queensland species (P. assimilis, P. sharmani, P. mareeba, P. godmani and P. coenensis) or the sampled intraspecific taxa of P. lateralis (P. l . lateralis, P. l. pearsoni, MacDonnell Ranges race). These results are consistent with previous studies in demonstrating that P. penicillata, P. purpureicollis, P. lateralis and P. inornata are genically distinct and that the north-east Queensland species and subspecies/races of P. lateralis form two groups of very closely related taxa. Future research should target more rapidly evolving DNA regions, in order to identify specific molecular markers that distinguish amongst taxa within these two groups. Meanwhile, karyotypic analysis remains the only definitive technique currently available to unambiguously identify all taxa within the lateralis–penicillata group.

scholarly journals Development of Contamination-Free Restriction Fragment Length Polymorphism Probes for the Obligate Biotroph Peronospora tabacina, an Oomycete Causing Blue Mold of Tobacco

2002 ◽  
Vol 92 (11) ◽  
pp. 1227-1235 ◽  
Author(s):  
Serenella A. Sukno ◽  
Amy M. Taylor ◽  
Mark Farman
Keyword(s):  
Molecular Markers ◽  
Sequence Analysis ◽  
Restriction Fragment Length Polymorphism ◽  
Restriction Fragment ◽  
Length Polymorphism ◽  
Fragment Length ◽  
Fragment Length Polymorphism ◽  
Blue Mold ◽  
Peronospora Tabacina ◽  
Restriction Fragment Length

Peronospora tabacina is an obligately parasitic oomycete that causes blue mold, a devastating disease of tobacco. Genetic studies of this pathogen have been hampered by the lack of molecular markers. We generated a set of molecular markers for P. tabacina by collecting sporangiospores from infected tobacco leaves, extracting spore DNA, and cloning it in a plasmid vector. The resulting clones were then used to probe DNA from a collection of P. tabacina isolates to survey for polymorphisms. Most probes gave unexpected hybridization patterns with signal intensities that varied significantly from one DNA sample to another or between different DNA preparations of the same isolate. These results indicated that certain DNA preparations contained DNA from a source other than P. tabacina, which in turn suggested that some probes might have been derived from contaminating organisms present in the spore suspensions. Therefore, we characterized the inserts of several recombinant plasmids to determine their origins. Sequence analysis revealed that several of the inserts encoded peptides with similarity to bacterial proteins, suggesting that they were derived from bacterial contaminants. Of the remaining clones, five exhibited similarity to retroelements, one resembled eukaryotic helicase genes, and nine had no similarity to sequences in the databases. These were postulated to be true P. tabacina DNA clones. Verification of the origin of each probe was achieved by filtering a spore suspension, extracting DNA from the retentate and filtrate, and probing Southern blots of these DNA samples. These experiments confirmed the probe origins predicted by sequence analysis, resulting in the generation of 20 different restriction fragment length polymorphism probes that are specific for P. tabacina DNA. These probes should enable identification of reliable genetic markers for population studies of the blue mold organism.

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