How to Perform an Accurate Analysis of Metaphase I Chromosome Configurations in Autopolyploids of Arabidopsis Thaliana

Abstract

During meiosis, accurate segregation of chromosomes requires the formation of bivalents at metaphase I. In autopolyploids, there are more than two copies of each chromosome with the same chance to form chiasmata at meiosis. This leads to the formation of multivalent configurations in which chiasma quantification is rather complicated. Here, we present an improved cytological protocol, including fluorescence in situ hybridization, to obtain high quality spreads of metaphase I chromosomes from Arabidopsis thaliana autotetraploids. This method allows an accurate analysis of the different meiotic configurations and enables the assessment of the number of chiasmata formed by each tetrasome (group of four homologs).En los autopoliploides hay más de dos copias de cada cromosoma, lo que lleva a la formación de configuraciones meióticas complejas (multivalentes). En este capítulo, presentamos un protocolo para optimizar la observación citológica de estas configuraciones en la metafase I de la meiosis, aplicando hibridación in situ con fluorescencia, con el objetivo de mejorar la interpretación de los multivalentes en autotetraploides de la especie modelo Arabidopsis thaliana.