title: Chiasmatic and achiasmatic inverted meiosis of plants with holocentric chromosomes.
abstract: Meiosis is a specialized cell division in sexually reproducing organisms before gamete formation. Following DNA replication, the canonical sequence in species with monocentric chromosomes is characterized by reductional segregation of homologous chromosomes during the first and equational segregation of sister chromatids during the second meiotic division. Species with holocentric chromosomes employ specific adaptations to ensure regular disjunction during meiosis. Here we present the analysis of two closely related plant species with holocentric chromosomes that display an inversion of the canonical meiotic sequence, with the equational division preceding the reductional. In-depth analysis of the meiotic divisions of Rhynchospora pubera and R. tenuis reveals that during meiosis I sister chromatids are bi-oriented, display amphitelic attachment to the spindle and are subsequently separated. During prophase II, chromatids are connected by thin chromatin threads that appear instrumental for the regular disjunction of homologous non-sister chromatids in meiosis II.
authors.affiliation: 1] Department of Botany, Laboratory of Plant Cytogenetics and Evolution, Federal University of Pernambuco, Rua Nelson Chaves s/n, Recife, Pernambuco 50670-420, Brazil [2] Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, Dr Bohr-Gasse 9, Vienna A-1030, Austria.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Cabral
authors.affiliation: Department of Botany, Laboratory of Plant Cytogenetics and Evolution, Federal University of Pernambuco, Rua Nelson Chaves s/n, Recife, Pernambuco 50670-420, Brazil.
authors.forename: André
authors.initials: A
authors.lastname: Marques
authors.affiliation: Leibniz Institute of Plant Genetics and Crop Plant Research, Corrensstraße 3, Gatersleben 06466, Germany.
authors.forename: Veit
authors.initials: V
authors.lastname: Schubert
authors.affiliation: Department of Botany, Laboratory of Plant Cytogenetics and Evolution, Federal University of Pernambuco, Rua Nelson Chaves s/n, Recife, Pernambuco 50670-420, Brazil.
authors.forename: Andrea
authors.initials: A
authors.lastname: Pedrosa-Harand
authors.affiliation: Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, Dr Bohr-Gasse 9, Vienna A-1030, Austria.
authors.forename: Peter
authors.initials: P
authors.lastname: Schlögelhofer
mesh_terms: D002503:Centromere; D002843:Chromatin; D023902:Chromosome Pairing / Q000502:physiology; D020090:Chromosome Segregation / Q000502:physiology; D032461:Chromosomes, Plant / Q000502:physiology*; D029785:Cyperaceae / Q000502:physiology*; D008540:Meiosis / Q000502:physiology*
chemical_list: D002843:Chromatin