Chromosome location of Oryza sativa recombination linkage groups.

Abstract

In situ hybridization, a powerful tool for the molecular cytogenetlcist, can be used to physically map repetitive, low-copy, and unique DNA sequences in plant chromosomes. With the availability of a recombination map in Oryza sativa L. and an improved in situ hybridization technique, this study was designed to esablh the relationship between the genetic and physical distances of the rice restriction agment length polymorphism map. Analysis indicated that considerable variation can exist between genetic and physical maps. A 183-centimorgan linkage map for chromosome 2 covered <50% of the chromosome and did not include the centromere, whereas a 91-centmorgan linkage map for chromosome 1 covered '80% of the chromosome. The results indicated that there are potential "hot" and "cold" spots of recombination and polymorphisms in rice, which involve both genes and restriction frgment length polymorphisms.

Chromosomal differentiation in Helianthus annuus var. macrocarpus: heterochromatin characterization and rDNA location

“…These chromosomal markers could be useful either from the taxonomic point of view to identify chromosomes from different genomes or to follow the introgression of alien chromosomes in cultivated sunflowers, as happens in other plant species (Gustafson & Dille, 1992;Werner et al, 1992). In any case, the existence of linkage maps in the sunflower (Rieseberg et al, 1993;Gentzbittel et a!., 1995) where ribosomal gene polymorphisms have been described (Choumane & Heizmann, 1988) might permit the chromosomes with NORs to be assigned to linkage groups.…”

Metaphase and interphase fluorescence in situ hybridization mapping of the rice genome with bacterial artificial chromosomes.

“…In most of the successful in situ hybridization experiments in plants, the target DNA sequences on chromosomes were >10 kb long (10)(11)(12)(13)(14). Mapping of small probes was also reported (15); however, the frequency of signal detection was very low and the technique is not very reliable and reproducible (9). The §To whom reprint requests should be addressed.…”

Cytogenetic mapping in maize

“…In these techniques, the probe is labeled with a hapten, such as biotin or digoxigenin, and the hybridization sites are detected by enzymes (enzymatic detection) or fluorochromes (fluorescent detection or FISH) coupled to avidin or anti-hapten antibodies (for details of these techniques, see Schwarzacher and Heslop-Harrison, 2000). In plants, the enzymatic detection was first used to localize repetitive sequences (Rayburn and Gill, 1985), and later was shown to be feasible for mapping of low-and single-copy sequences (Gustafson and Dille, 1992;Ren et al, 1997). However, enzymatic detection is now mostly superseded by FISH in cytogenetic mapping.…”