title: Cytological and molecular analysis of centromere misdivision in maize.
abstract: B chromosome derivatives suffering from breaks within their centromere were examined cytologically and molecularly. We showed by high resolution FISH that misdivision of the centromere of a univalent chromosome can occur during meiosis. The breaks divide the centromere repeat sequence cluster. A telocentric chromosome formed by misdivision was found to have the addition of telomeric repeats to the broken centromere. A ring chromosome formed after misdivision occurred by fusion of the broken centromere to the telomere. Pulsed-field electrophoresis analyses were performed on the telocentric and ring chromosomes to identify fragments that hybridize to both the telomeric repeat and the B-specific centromeric repeat. We conclude that healing of broken maize centromeres can be achieved through the mechanisms of addition or fusion of telomeric repeat sequences to the broken centromere.
authors.affiliation: Division of Biological Sciences, University of Missouri, Columbia 65211, USA.
authors.forename: Etienne
authors.initials: E
authors.lastname: Kaszás
authors.forename: Akio
authors.initials: A
authors.lastname: Kato
authors.forename: James A
authors.initials: JA
authors.lastname: Birchler
mesh_terms: D002503:Centromere / Q000235:genetics*; D002869:Chromosome Aberrations; D016521:Electrophoresis, Gel, Pulsed-Field; D017404:In Situ Hybridization, Fluorescence; D008540:Meiosis / Q000502:physiology*; D008938:Mitosis / Q000502:physiology; D012091:Repetitive Sequences, Nucleic Acid; D003313:Zea mays / Q000235:genetics*