Comparative genetic studies have shown that there are widespread synteny and colinearity of the genes among different species within grass family. Rice ( Oryza sativa L.) is a model plant, and analysis of its genome allows us to reveal the common features and the evolutionary rules of the gramineous genomes and accumulate the data for establishment of a common genetic system in the Poaceae. In this study, a rice gene Pib ( 10.3 kb), a map-based cloned gene, and RFLP markers linked with it are used as the tested probes to investigate their homology and physical location among the tested species. Southern blotting analysis showed that there were sequences homologous to Pib in maize genome. Further, Pib was localized onto the chromosomes of O. sativa ssp. indica cv. Guangluai 4, O. officinalis Wall ex Watt and the inbred line of Zea mays cv. Huangzao 4. The results of fluorescence in situ hybridization (FISH) and double-color FISH indicated that a synteny of Pib and RFLP markers linked with Pib existed among the genomes of the three tested species.
The techniques of in situ hybridization (ISH) are widely adopted for analyzing the genetic make_up and RNA expression patterns of individual cells. There are four main criterions for evaluating this technique, including detection sensitivity, resolution, capacity and specificity. This review focuses on a number of advances made over the last years in the fluorescence in situ hybridization (FISH). These advances can be catagorized into several branches as follows: (1) Multicolor_FISH (mFISH), including conventional mFISH, combinatorial FISH, ratio labelling FISH, multicolor chromosome painting and comparative genomic hybridization (CGH); (2) Extended DNA fiber_FISH (EDF_FISH), including quantitative DNA fiber mapping (QDFM), molecular combing (MC) and dynamic molecular combing (DMC); (3) In situ PCR_based FISH; (4) Bacterial (or yeast) artificial chromosome_FISH (BAC_FISH or YAC_FISH); (5) Tyramide signal amplification_FISH (TSA_FISH); (6) Polypeptide nucleic acid_FISH (PNA_FISH) and (7) padlock_FISH.
