Meiotic transmission rates correlate with physical features of rearranged centromeres in maize.
The centromere of the maize B chromosome was used as a model to study the physical features of a functional centromere. Pulsed-field gel electrophoresis was previously used to determine the organization of a repetitive sequence (referred to as the B-specific repeat) localized in the centromeric region of the maize B chromosome. The centromere is composed mostly of this repeat. In this report, a collection of 25 B chromosome derivatives that suffered from misdivision of the centromere was examined for the content and organization of the B repeat. Meiotic transmission of these derivatives was also determined and compared with rearrangements within the centromere. This analysis revealed that there is a strong correlation between the size of the centromere and meiotic transmission. In addition, the loss of a particular PmeI fragment of 370 kb considerably reduced meiotic transmission. This sequence contains a 55-kb EcoRI fragment that is also present in all but four derivatives. Because the centromere of the maize B chromosome can be divided by successive misdivisions to derivatives with centromeres of <300 kb, it should be possible for artificial chromosomes to be produced in maize.
Kaszás
E
E
Division of Biological Sciences, University of Missouri, Columbia, Missouri 65211, USA.
Birchler
J A
JA
D002503:Centromere; D015252:Deoxyribonucleases, Type II Site-Specific; D018628:Gene Dosage; D015321:Gene Rearrangement; D017343:Genes, Plant; D008540:Meiosis; D003313:Zea mays / Q000235:genetics*
C078388:endodeoxyribonuclease PmeI; D015252:Deoxyribonucleases, Type II Site-Specific