Cytological and molecular analysis of centromere misdivision in maize.
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.
Kaszás
Etienne
E
Division of Biological Sciences, University of Missouri, Columbia 65211, USA.
Kato
Akio
A
Birchler
James A
JA
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*