Study on Diffused Centromeric Nature of Drosera Chromosomes

抄録

Drosera dichrosepala was exposed to different doses of Gamma radiation. Fragmented and fused chromosomes were observed as a consequences. Diffused centromeres in every fragment chromosome was detected by centromeric banding (Cd-banding) and was supported by its typical disjunction and totally lack of lagging chromosomes or micronuclei from anaphase to telophase. C-banding revealed that the fragment chromosomes were highly heterochromatic and fragmentation might be occurred at the terminal regions of chromosomes. Fluorescent banding suggested that most of the fragment chromosomes were rich in GC base composition in the species. Alteration of karyotype due to Gamma irradiation also indicated that spontaneous fragmentation or fusion of chromosomes might be a possible factor for promoting the bimodal karyotype in this genus.