scholarly journals A method for mapping germ line sequences in Tetrahymena thermophila using the polymerase chain reaction.

Genetics ◽  
1994 ◽  
Vol 137 (1) ◽  
pp. 95-106 ◽  
Author(s):  
D Cassidy-Hanley ◽  
M C Yao ◽  
P J Bruns

Abstract A method for mapping DNA sequences to specific germinal chromosomes in the ciliated protozoan Tetrahymena thermophila has been developed. This mapping technique (PCR mapping) utilizes the polymerase chain reaction and template DNA derived from nullisomic strains to directly assign micronuclear DNA sequences to specific micronuclear chromosomes. Using this technique, a number of unique sequences and short repetitive sequences flanked by unique sequences have been mapped to four of the five germinal chromosomes.

1999 ◽  
Vol 47 (3) ◽  
pp. 351-359 ◽  
Author(s):  
S. Omanwar ◽  
J. R. Rao ◽  
G. Butchaiah ◽  
S. H. Basagoudanavar ◽  
R. K. Singh

The mechanically transmitted haemoflagellate,Trypanosoma evansicauses 'surra', a wasting disease of domestic animals and is highly endemic in distribution in Southeast Asia. The detection ofT. evansiis important for improving the epizootiological and animal health status of the region. The specificity and sensitivity of polymerase chain reaction (PCR) using oligonucleotide primers constructed fromT. evansirepetitive DNA sequences were studied in the present investigation. Using the assay, it was possible to amplify template DNA ofT. evansiderived from buffaloes, camels and horses to a threshold sensitivity level of 0.5 pg and to detect DNA from as few as five organisms in 10 (l crude blood samples. Following experimental infection of calves with 5 × 105T. evansi, positive signals could be observed as early as 12 h post-infection. DNAs from two common haemoflagellates of cattle,Babesia bigeminaandTheileria annulatawere not amplified with the primers.


2014 ◽  
Vol 104 (3) ◽  
pp. 233-237 ◽  
Author(s):  
María José Iglesias Sánchez ◽  
Ana María Pérez Pico ◽  
Félix Marcos Tejedor ◽  
María Jesús Iglesias Sánchez ◽  
Raquel Mayordomo Acevedo

Background Dermatomycoses are a group of pathologic abnormalities frequently seen in clinical practice, and their prevalence has increased in recent decades. Diagnostic confirmation of mycotic infection in nails is essential because there are several pathologic conditions with similar clinical manifestations. The classical method for confirming the presence of fungus in nail is microbiological culture and the identification of morphological structures by microscopy. Methods We devised a nested polymerase chain reaction (PCR) that amplifies specific DNA sequences of dermatophyte fungus that is notably faster than the 3 to 4 weeks that the traditional procedure takes. We compared this new technique and the conventional plate culture method in 225 nail samples. The results were subjected to statistical analysis. Results We found concordance in 78.2% of the samples analyzed by the two methods and increased sensitivity when simultaneously using the two methods to analyze clinical samples. Now we can confirm the presence of dermatophyte fungus in most of the positive samples in just 24 hours, and we have to wait for the result of culture only in negative PCR cases. Conclusions Although this PCR cannot, at present, substitute for the traditional culture method in the detection of dermatophyte infection of the nails, it can be used as a complementary technique because its main advantage lies in the significant reduction of time used for diagnosis, in addition to higher sensitivity.


Genome ◽  
1992 ◽  
Vol 35 (4) ◽  
pp. 621-626 ◽  
Author(s):  
Peter M. Rogowsky ◽  
Ken W. Shepherd ◽  
Peter Langridge

A novel type of polymerase chain reaction (PCR) marker was developed for the mapping of cereal rye (Secale cereale). Primer pairs were synthesized targeting the insertion sites of three individual copies of the R173 family of rye specific repeated DNA sequences. While one primer was derived from a sequence within the respective R173 element, the second primer corresponded to a flanking region. The complex banding patterns obtained in rye allowed not only the mapping of the three R173 elements to certain chromosome regions of 1RS (the short arm of rye chromosome 1) but also the mapping of an additional 3–10 easily identifiable bands per primer pair to other rye chromosomes. Linkage mapping of a polymorphic 1R band derived from three rye cultivars demonstrated the presence of nonallelic, dominant markers in two independent crosses. Because of the high copy number of the R173 family (15 000 copies per diploid rye genome), its dispersion over the entire length of all chromosomes and the high number of markers obtained per primer pair, PCR markers based on the R173 family provide an almost unlimited source for well-spaced markers in rye mapping.Key words: polymerase chain reaction, mapping, repetitive DNA sequences, wheat, rye.


Genome ◽  
1993 ◽  
Vol 36 (1) ◽  
pp. 50-56 ◽  
Author(s):  
Kemal Kazan ◽  
John M. Manners ◽  
Don F. Cameron

The inheritance of random amplified polymorphic DNA (RAPD) markers generated via the polymerase chain reaction amplification of genomic DNA sequences in an F2 family of an interspecific cross between Stylosanthes hamata and S. scabra was investigated. An initial comparison between the parental species, S. hamata cv. Verano and S. scabra cv. Fitzroy, demonstrated that 34% of detected RAPD bands were polymorphic. Of 90 primers tested, 35 showed relatively simple and reliably scorable polymorphisms and were used for segregation analysis. Sixty F2 individuals were scored for the segregation of 73 RAPD markers and 55 of these markers fit a 3:1 ratio. Segregation of eight other RAPD markers deviated significantly from a 3:1 ratio. There was no bias in the inheritance of RAPD markers regarding parental origin of the segregating RAPD markers. Linkage analysis revealed 10 linkage groups containing a total of 44 RAPD loci. Another 10 RAPD markers (7 of maternal origin) that were polymorphic between the parents did not segregate in the F2 population. One of the maternally inherited RAPD bands hybridized to chloroplast DNA. Analysis of RAPD loci by DNA hybridization indicated that mainly repeated sequences were amplified. These data indicate that RAPDs are useful genetic markers in Stylosanthes spp. and they may be suitable for genetic mapping.Key words: genetic mapping, molecular markers, polymerase chain reaction, Stylosanthes hamata, Stylosanthes scabra.


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