title: Alternative meiotic chromatid segregation in the holocentric plant Luzula elegans.
abstract: Holocentric chromosomes occur in a number of independent eukaryotic lineages. They form holokinetic kinetochores along the entire poleward chromatid surfaces, and owing to this alternative chromosome structure, species with holocentric chromosomes cannot use the two-step loss of cohesion during meiosis typical for monocentric chromosomes. Here we show that the plant Luzula elegans maintains a holocentric chromosome architecture and behaviour throughout meiosis, and in contrast to monopolar sister centromere orientation, the unfused holokinetic sister centromeres behave as two distinct functional units during meiosis I, resulting in sister chromatid separation. Homologous non-sister chromatids remain terminally linked after metaphase I, by satellite DNA-enriched chromatin threads, until metaphase II. They then separate at anaphase II. Thus, an inverted sequence of meiotic sister chromatid segregation occurs. This alternative meiotic process is most likely one possible adaptation to handle a holocentric chromosome architecture and behaviour during meiosis.
authors.affiliation: Department of Cytogenetics and Genome Analysis, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstraße 3, 06466 Gatersleben, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Heckmann
authors.affiliation: Department of Cytogenetics and Genome Analysis, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstraße 3, 06466 Gatersleben, Germany.
authors.forename: Maja
authors.initials: M
authors.lastname: Jankowska
authors.affiliation: Department of Cytogenetics and Genome Analysis, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstraße 3, 06466 Gatersleben, Germany.
authors.forename: Veit
authors.initials: V
authors.lastname: Schubert
authors.affiliation: Department of Cytogenetics and Genome Analysis, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstraße 3, 06466 Gatersleben, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Kumke
authors.affiliation: Department of Cytogenetics and Genome Analysis, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstraße 3, 06466 Gatersleben, Germany.
authors.forename: Wei
authors.initials: W
authors.lastname: Ma
authors.affiliation: Department of Cytogenetics and Genome Analysis, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstraße 3, 06466 Gatersleben, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Houben
mesh_terms: D002503:Centromere / Q000378:metabolism*; D002842:Chromatids / Q000235:genetics*; D020090:Chromosome Segregation / Q000502:physiology*; D017404:In Situ Hybridization, Fluorescence; D019684:Magnoliopsida / Q000502:physiology*; D008540:Meiosis / Q000502:physiology*; D008856:Microscopy, Fluorescence