Biomedical subjects

T Joobeur

Publications and source records attributed to T Joobeur.

3 recordsLinked to original sources

PubMed2006

Construction of a watermelon BAC library and identification of SSRs anchored to melon or Arabidopsis genomes.

A bacterial artificial chromosome (BAC) library was constructed for watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai var. lanatus) with an average insert-size of 106 kb, providing 21 haploid genome equivalents. The library was used to identify BAC clones that are anchored to probes evenly distributed on the genomes of melon or Arabidopsis. Twenty eight probes (representing 66% of the tested probes) from melon and 30 probes (65%) from Arabidopsis identified positive BAC clones. Two methods were implemented to identify SSRs from the positively hybridizing BAC clones. First, analysis of BAC end sequences revealed 37 SSRs. For the second method, pooled DNA of BACs identified by the melon probes was used to develop a shotgun library. The library was then screened with synthetic SSR oligonucleotides by hybridization. Sequence analysis of positively hybridizing shotgun clones revealed 142 different SSRs. Thirty eight SSRs were characterized using three watermelon cultivars, five plant introduction (PI) accessions of C. lanatus var lanatus and four PIs of C. lanatus var citroides. Of these, 36 (95%) were found to be polymorphic with up to six alleles per marker. Polymorphism information content values for polymorphic markers varied between 0.22 and 0.79 with an average of 0.53. The methods described herein will be valuable for the construction of a watermelon linkage map with SSRs evenly distributed on its genome that is anchored to the genomes of melon and Arabidopsis.

Alleles↗

PubMed2001

Melon bacterial artificial chromosome (BAC) library construction using improved methods and identification of clones linked to the locus conferring resistance to melon Fusarium wilt (Fom-2).

Utilizing improved methods, two bacterial artificial chromosome (BAC) libraries were constructed for the multidisease-resistant line of melon MR-1. The HindIII library consists of 177 microtiter plates in a 384-well format, while the EcoRI library consists of 222 microtiter plates. Approximately 95.6% of the HindIII library clones contain nuclear DNA inserts with an average size of 118 kb, providing a coverage of 15.4 genome equivalents. Similarly, 96% of the EcoRI library clones contain nuclear DNA inserts with an average size of 114 kb, providing a coverage of 18.7 genome equivalents. Both libraries were evaluated for contamination with high-copy vector, empty pIndigoBac536 vector, and organellar DNA sequences. High-density filters were screened with two genetic markers FM and AM that co-segregate with Fom-2, a gene conferring resistance to races 0 and 1 of Fusarium wilt. Fourteen and 18 candidate BAC clones were identified for the FM and AM probes, respectively, from the HindIII library, while 34 were identified for the AM probe from filters A, B, and C of the EcoRI library.

Chromosomes, Artificial, Bacterial↗

PubMed2000

Development of a second generation linkage map for almond using RAPD and SSR markers.

Fifty-four RAPD (random amplified polymorphic DNA) markers and 6 SSRs (simple sequence repeats) were included in a molecular marker map with 120 RFLPs (restriction fragment length polymorphisms) and 7 isozyme genes previously constructed using the offspring of a cross between the almond (Prunus amygdalus) cultivars 'Ferragnès' and 'Tuono'. Only highly reproducible RAPDs segregating 1:1 were used. To identify these markers, a total of 325 primers were screened, from which 41 produced RAPDs useful for mapping. Polymorphism was detected in six of the eight Prunus SSRs (simple sequence repeats) studied, thus enabling these to be mapped. All markers were placed on the 8 linkage groups previously identified. The number of new markers included in the map of 'Ferragnès' was 33 for a total of 126, and 30 in the map of 'Tuono' for a total of 99. The sizes of the maps of 'Ferragnès' (415 cM) and 'Tuono' (416 cM) were similar, representing a 5% increase over the maps constructed solely with isozymes and RFLPs. The estimated total size of the almond map was of 457 cM. Some markers were placed in zones with low density of markers and others in the extreme of linkage groups. The use of RAPD markers to complete genetic maps constructed with transferable markers is discussed.

Chromosome Mapping↗