The first cytological maps in plants were based on natural features such as centromeres, the nucleolus organizing regions, and euchromatin-heterochromatin boundaries. Subsequently, researchers identified and used stains such as quinacrine and Giemsa to stain types of chromatin, such as AT-rich regions, differentially. Cytology was instrumental in mapping various chromosomal rearrangements. Electron microscopy has also proven to be a powerful tool, permitting three-dimensional reconstruction of chromosomes from whole-nucleus preparations as well as providing a direct link between linkage and physical distance by localization of recombination nodules on synaptonemal-complex spreads. The application of in situ hybridization (ISH) greatly advanced plant cytogenetic mapping. The development of nonradioactive probe-labeling techniques, such as biotinylation and more recently fluorescence, has made ISH an accessible method for the localization of specific nucleic-acid sequences along the physical chromosomes of plants. A variety of DNA probes have been used in plant cytogenetic mapping, including genetic marker sequences, large DNA fragments, and repetitive sequences. Several tissues and techniques have been used to prepare target chromosomes for mapping, each affording different advantages and disadvantages with regard to resolution and availability. Recently, additional techniques have been developed that elongate chromosomes for even higher resolution. Cytogenetic mapping has proven useful for observing genome organization, and much research is currently focused on integration of plant cytological and linkage maps.
|Title of host publication||Plant Cytogenetics|
|Subtitle of host publication||Genome Structure and Chromosome Function|
|Publisher||Springer New York|
|Number of pages||41|
|State||Published - Jan 1 2012|
- Fluorescence in situ hybridization (FISH)
- Probe detection and resolution