Image analysis of small plant chromosomes by using an improved system, CHIAS IV

Small plant chromosomes show uneven condensation during the prometaphase stage in mitosis. Recently, an improved chromosome image analyzing system (CHIAS IV) has been released for measurement of the condensation patterns (CPs) in fluorescence images. CHIAS IV is based on the multiplatform public-domain image-processing software, ImageJ, which was developed by the National Institutes of Health, US. In this study, we used CHIAS IV to perform image analysis of the fluorescence patterns of somatic prometaphase chromosomes of the leguminous plant, red clover (Trifolium pratense L., 2n = 2x = 14). We produced a quantitative chromosome map of red clover by combining the qualitative-analysis results obtained using fluorescence in situ hybridization (FISH) mapping with the results of the CHIAS IV imageanalysis method, thereby clearly demonstrating the effectiveness and utility of this software as an analytical tool for genetic and genomic studies.