Specific RAPD Markers Research Articles

The Use of Random Amplified Polymorphic DNA (RAPD) Markers for the Study of Taxonomical Relationships Among Species of Asphodelus Sect. Verinea (Asphodelaceae)

RAPD analysis was applied to the three species of Asphodelus sect. Verinea (Pomel) Boissier (Asphodelaceae): Asphodelus fistulosus L., A. ayardii Jahand. & Maire, and A. tenuifolius Cav. Fifteen populations, five per species, were used and eight primers were sampled. A total of 97 amplification products were generated, and 4–12 polymorphic products per primer were obtained. Several specific RAPD markers were detected for A. ayardii and A. tenuifolius, while only two for A. fistulosus, which shares most amplification products with the two former species. Results that reinforce the specific status of the three taxa are shown. Asphodelus tenuifolius showed the highest interpopulation variability in agreement with the high specialization of other characters in this species. In accordance with these results, an amphidiploid origin for A. fistulosus, with the participation of A. ayardii and A. tenuifolius, is suggested.

Inheritance of oilseed rape (Brassica napus) RAPD markers in a backcross progeny with Brassica campestris

Different cultivars/transgenic lines of oilseed rape (Brassica napus) were crossed (as females) with different cultivars/populations of Brassica campestris. All cross combinations produced seed, with an average seed set per pollination of 9.8. Backcrossing of selected interspecific hybrids (as females) to B. campestris resulted in a much lower seed set, average 0.7 seed per pollination. In the single backcross progeny where a large enough population (92 plants) was obtained for analysis, 33 B. napus specific RAPD markers were investigated to determine the extent of transfer of oilseed rape genetic material into this population. Markers were transferred to the backcross generation with frequencies ranging from 26% to 91%. Almost all of the markers (30/33) were transferred in a frequency not significantly different from 50%. Analysis of the pairwise segregation of markers revealed that 23 markers could be assigned to six linkage groups, most probably reflecting six B. napus C-chromosomes. The presence of backcross plants with recombinant genotypes suggests that complex genetic processes can take place during interspecific hybridisation and backcrossing in these Brassica species. The implications of our results for the possible choice of integration sites of transgenes in oilseed rape are discussed.

Production and characterization of haploids derived from somatic hybrids between Solanum brevidens and S. tuberosum through anther culture

Somatic hybrids between dihaploid (2 n=2 x=24) cultivated potato Solanum tuberosum L.) and diploid (2 n=2 x=24), virus resistant wild potato species S. brevidens Phil., were tested for their feasibility for anther culture. A total of 17 shoots regenerated by embryogenesis from anthers of the hybrids. Five regenerants survived and were grown in vitro and in the greenhouse. The haploids were morphologically intermediate between S. brevidens and S. tuberosum. They were analysed for S. brevidens specific and S. tuberosum specific RAPD markers using four primers, and were found to contain the S. brevidens specific DNA markers and most of the S. tuberosum specific markers. The chromosome numbers of the haploids ranged from 34 to 36. According to flow cytometric analysis, the nuclear DNA contents of the haploids (2 C=2.15–2.30pg) were approximately half of the hexaploid somatic hybrids (2 C=4.47–4.53pg). The somatic hybrids were identified as chimeric (hypohexaploids), whereas the haploids derived from them using anther culture were all triploids according to flow cytometry. The haploids were extremely resistant to potato leaf roll virus.

Arbitrary Single Short Primers Identify Polymorphic DNA Markers That Distinguish Inbred Strains of Mice

The inbred mouse strains, Balb/c and SJL/J, have been widely used in biomedical research to unravel the genetic basis of susceptibility to tumors, viral diseases, autoimmune encephalitis, atopic disorders and neuro-retinopathies. In this study we attempted to identify DNA polymorphisms that distinguish them using RAPD assay. Screening of the genomic DNA of mice with a panel of 100 random decamer primers led to the identification of 36 primers which amplified 204 strain specific RAPD markers. On an average each of the selected primer amplified 11 bands of which 5.6 were strain specific. Segregation of RAPD markers in a (Balb/c × SJL/J) Fl × SJL/J backcross progeny (n=6) suggested that the markers are potentially suitable for molecular genetic linkage studies.