DEVELOPMENT OF A QUANTITATIVE CHROMOSOME MAP OF Arabidopsis BY IMAGING METHODS

¹ Faculty of Horticulture, Chiba University, Mastudo 271-8510, Japan

² Hokuriku National Agricultural Experiment Station, Joetsu 943-0193, Japan

³ Faculty of Engineering, Graduate School of Osaka University, Suita 565-0871, Japan

Arabidopsis is widely used as a model plant in genetics and molecular biology. In recent years, sequencing of the entire Arabidopsis genome has been proceeded and genome information has been accumulated using molecular biological techniques. Whereas, information of the chromosomes in Arabidopsis is few. Arabidopsis has very small chromosomes which are similar in morphology. Therefore it was difficult to distinguish and identify its ten chromosomes. The present study has been carried out with the aims to characterize the Arabidopsis chromosomes by molecular cytogenetical techniques. Pro-metaphase chromosomes stained with a Giemsa solution were identified and characterized with chromosome length and condensation patterns using CHIAS III (chromosome image analyzing system III). All chromosomes were characterized by condensation patterns. Moreover, 45S and 5S rDNAs were localized accurately on the chromosomes using FISH (fluorescent in situ hybridization). As a result, it becomes possible to identify all the chromosomes by the imaging methods and physical mapping of rDNAs. Cytological information on somatic chromosomes of Arabidopsis would be useful for its further genome research.