Fluorescent In Situ Hybridization of 25S rDNA and Telomere Probes in the Lamium amplexicaule Chromosomes and their Signals Behavior during Meiosis

抄録

Pairing of homologous chromosomes (HCs) during meiosis is a vital process for the production of normal haploid gametes and fertile progeny. However, the pairing process, especially its initial steps, shows diversity among organisms and has not been fully understood. In order to expand our knowledge of plant meiosis, the behaviors of telomeres and 25S rRNA loci in Lamium amplexicaule (2n=18) were investigated using fluorescent in situ hybridization (FISH) experiments. Telomere signals were detected on small knot-like structures at the pachytene stage and on all nine bivalents at diakinesis. 25S rDNA signals were found on three bivalents, indicating that the L. amplexicaule genome has three 25S rRNA loci. During the prophase of meiosis I, 25S rDNA signals were observed approaching each other and frequently merging into a single cluster. Our results suggest that the clustering of 25S rRNA loci in L. amplexicaule could play a role in promoting homolog pairing at prophase I.