Chromosomes form into seven groups in hexaploid and tetraploid wheat as a prelude to meiosis.

Hexaploid wheat possesses 42 chromosomes derived from its three ancestral genomes. The 21 pairs of chromosomes can be further divided into seven groups of six chromosomes (one chromosome pair being derived from each of the three ancestral genomes), based on the similarity of their gene order. Previous studies have revealed that, during anther development, the chromosomes associate in 21 pairs via their centromeres.

Functional dissection of in vivo interchromosome association in Saccharomyces cerevisiae.

Homologue pairing mediates both recombination and segregation of chromosomes at meiosis I. The recognition of nucleic-acid-sequence homology within the somatic nucleus has an impact on DNA repair and epigenetic control of gene expression. Here we investigate interchromosomal interactions using a non-invasive technique that allows tagging and visualization of DNA sequences in vegetative and meiotic live yeast cells.

The condensin complex governs chromosome condensation and mitotic transmission of rDNA.

We have characterized five genes encoding condensin components in Saccharomyces cerevisiae. All genes are essential for cell viability and encode proteins that form a complex in vivo. We characterized new mutant alleles of the genes encoding the core subunits of this complex, smc2-8 and smc4-1.

Homologous chromosome pairing in wheat.

Bread wheat is a hexaploid (AABBDD, 2n=6x=42) containing three related ancestral genomes, each having 7 chromosomes, giving 42 chromosomes in diploid cells. During meiosis true homologues are correctly associated in wild-type wheat, but a degree of association of related chromosomes (homoeologues) occurs in a mutant (ph1b). We show that the centromeres are associated in non-homologous pairs in all floral tissues studied, both in wild-type wheat and the ph1b mutant.

Transcription sites are not correlated with chromosome territories in wheat nuclei.

We have determined the relationship between overall nuclear architecture, chromosome territories, and transcription sites within the nucleus, using three-dimensional confocal microscopy of well preserved tissue sections of wheat roots. Chromosome territories were visualized by GISH using rye genomic probe in wheat/rye translocation and addition lines. The chromosomes appeared as elongated regions and showed a clear centromere-telomere polarization, with the two visualized chromosomes lying approximately parallel to one another across the nucleus.