A light microscopic atlas of meiosis in Arabidopsis thaliana.

An atlas of meiosis in Arabidopsis thaliana, encompassing all stages from preleptotene to telophase II and early microspore formation, is presented in detail for the first time. The photomicrographs and descriptions are based on staining with the DNA fluorochrome 4',6-diamidino-2-phenylindole (DAPI) combined with a spreading procedure, or haematoxylin-iron alum (HIA) staining. Despite previous reservations about the practicality of cytogenetic meiotic analysis in Arabidopsis due to its small genome size, good-quality and clearly analysable preparations of all meiotic stages were obtained. This atlas of normal, wild-type meiosis is considered an essential prerequisite to informed analyses of meiotic mutants. Furthermore, extended prophase I chromosomes, particularly at the pachytene stage, offer considerable potential for producing a detailed cytogenetic map (karyotype) of Arabidopsis chromosomes with the additional prospect of high-resolution physical mapping based on fluorescence in situ hybridization (FISH) of defined DNA probes to these extended chromosomes.