Evidences for continuous genome in Impatiens balsamina (Balsaminaceae)

Abstract

The connections between chromosomes through telomeres by chromatin- containing connectives are on record. In the present investigation these connectives are studied using acetic-orcein and acetic-carmine as well as DNAspecific Giemsa and fluorochrome staining methods in the various stages of mitosis in cells derived from both haploid and diploid phases of Impatiens balsamina L. (2n=14). Results of this study suggest that the fully disentangled, taut interchromosomal chromatin positive connectives between discrete chromosomes are inherent structures that reflect a continuous genome in this plant. During divisional stages, especially at metaphase, when chromosomes have become maximally coiled and folded, interchromosomal chromatin connectives are no longer resolvable. These results suggest that, in this plant, end-to-end chromosome connections may provide the physical basis for maintenance of the positional stability of the chromosomes throughout the cell cycle. The role of ordered chromosome topology is discussed in the light of the developing concepts. © 2003 Taylor & Francis Group, LLC.