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 image-analysis method, thereby clearly demonstrating the effectiveness and utility of this software as an analytical tool for genetic and genomic studies.

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Entire 5S ribosomal DNA (rDNA), including 120 bp of rRNA gene and 142 bp of non-transcribed spacer (NTS) regions of Psathyropus tenuipes (Arachnida, Opiliones, Sclerosomatidae), a harvestman which usually bears several B-chromosomes, was sequenced and mapped on the spermatogonial metaphases using fluorescence in-situ hybridization (FISH). The signals of 5S rDNA were detected on the terminal region of one pair of C-band-negative autosomal chromosomes, showing that the 5S rDNA cluster is localized to A chromosome in this species, but not to B chromosome known as a rDNA carrier in other arthropods.

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