Chromosome behavior with 45S rDNA loci at meiosis of Veronica persica

抄録

Meiosis is essential for gamete production, and involves two rounds of successive cell divisions, meiosis I and II. During prophase of meiosis I, chromosomes present meiosis-specific behavior, such as homologous chromosomes (HCs) pairing and synapsis. Here, we present the results found in the observation of meiosis in Veronica persica (2n = 28). The chromosome behavior of pollen mother cells (PMCs) at meiosis was evaluated via 4′,6-diamidino-2-phenylindole (DAPI)-staining and fluorescent in situ hybridization (FISH) using as the probes 5.8S rRNA and 25S rRNA-encoding sequences to detect 45S rDNA locus. DAPI staining confirmed the chromosome number and revealed conformational changes. The space occupied by the chromosomes within the PMCs seemed to shrink during late leptotene, which may assist HC pairing. 5.8S rDNA FISH signals were detected on seven bivalents, indicating that V. persica possesses seven 45S rDNA loci within its genome. Among the seven loci, some of them were associated with the nucleoli, but others were not. Taken together, this research has provided us new information concerning the overall and locus-specific dynamics of meiotic chromosomes in V. persica PMCs.