Simultaneous loss of two knobbed chromosomes induced by B chromosomes in maize

Chromosome elimination in maize induced by supernumerary B chromosomes.

The regular chromosomal complement of maize consists of 20 chromosomes. These are known as the A set and are invariably present in this number in all normal diploid plants. Heteropycnotic regions known as "knobs" are found in characteristic positions on the different A chromosomes, although the number of knobs varies greatly in different strains. Knobless races are known, while others have as m...

Chromosomes in Maize and Maize Relatives »

An understanding of the laws of heredity is essential if improvement of plant breeding is to be controlled intelligently. A comprehensive understanding of the mechanism of inheritance demands definite knowledge of the chromosome number, not only of the forms it is desirous to improve but also of the related species. The present paper presents the results of a study of the chromosome number in s...

Meiotic behavior of small chromosomes in maize

The typical behavior of chromosomes in meiosis is that homologous pairs synapse, recombine, and then separate at anaphase I. At anaphase II, sister chromatids separate. However, studies of small chromosomes in maize derived from a variety of sources typically have failure of sister chromatid cohesion at anaphase I. This failure occurs whether there is pairing of two copies of a minichromosome o...

Separation of lentil root tip chromosomes by colchicine

Chromosome nondisjunction and instabilities in tapetal cells are affected by B chromosomes in maize.

Abnormal mitosis occurs in maize tapetum, producing binucleate cells that later disintegrate, following a pattern of programmed cell death. FISH allowed us to observe chromosome nondisjunction and micronucleus formation in binucleate cells, using DNA probes specific to B chromosomes (B's), knobbed chromosomes, and the chromosome 6 (NOR) of maize. All chromosome types seem to be involved in micr...