title: Accumulation of multiple copies of maize minichromosomes.
abstract: Multiple copies of B chromosomes in maize (Zea mays) can accumulate in the genome using the B chromosome's accumulation mechanism, specifically nondisjunction at the second pollen mitosis and preferential fertilization of the egg. Using this mechanism, we accumulated 4 different-sized minichromosomes derived from the B chromosome to test the chromosome limits of the cell. The accumulation of normal B chromosomes is associated with multiple phenotypes including white stripes and asymmetric leaf blades, but when minichromosomes are accumulated these symptoms are absent. We also found that multiple B chromosome-derived minichromosomes can coexist with A chromosome-derived minichromosomes. During the years that these experiments were conducted, we found many B chromosome rearrangements and fragments, 2 recoverable A chromosome fragments, and observed a minichromosome breakage-fusion-bridge cycle in roots.
authors: Division of Biological Sciences, University of Missouri, Columbia, MO 65211, USA.
authors: R E
authors: RE
authors: Masonbrink
authors: J A
authors: JA
authors: Birchler
mesh_terms: D032461:Chromosomes, Plant; D017403:In Situ Hybridization; D007621:Karyotyping; D016133:Polymerase Chain Reaction; D003313:Zea mays / Q000235:genetics*