Comparative Cytogenetic of the 36-Chromosomes Genera of Orchidinae Subtribe (Orchidaceae) in the Mediterranean Region: A Summary and New Data

This article provides a summary of the current knowledge on the cytogenetics of four genera, which are all composed of 36 chromosomes, within the Orchidinae subtribe (Orchidaceae). Previous classical studies have revealed differences in karyomorphology among these genera, indicating genomic diversity. The current study includes an analysis of the current knowledge with an update of the karyotype of 47 species with 36 chromosomes from the genera Anacamptis, Serapias, Himantoglossum, and Ophrys. The study discusses comparisons of karyotypes among these genera that used traditional techniques as well as karyotype asymmetry relationships with various asymmetry indices. Additionally, the study reports new findings on polyploidy in Anacamptis pyramidalis and Serapias lingua, which were observed through karyotype and meiotic metaphase analyses in EMC. Moreover, the study detected B chromosomes for the first time in A. papilionacea and A. palustris. The article also describes the use of fluorescent in situ hybridization in some specimens of A. papilionacea and A. collina to locate different sites of the 18S-5.8S-25S rDNA and 5S rDNA ribosomal complexes on chromosomes. The information derived from these cytogenetic analyses was used to refine the classification of these orchids and identify evolutionary relationships among different species and genera.