The Mre11/Rad50/Nbs (MRN) complex and the two protein kinases ATM and ATR play critical roles in the response to DNA damage and telomere maintenance in mammalian systems. It has been previously shown that mutations in the Drosophila mre11 and rad50 genes cause both telomere fusion and chromosome breakage. Here, we have analyzed the role of the Drosophila nbs gene in telomere protection and the ...

Convention terminology. There follows a compilation of numerical abnormalities of chromosome constitution, again in order 1 to 22, X and Y. There is a table of syndromes associated with breakage syndromes. Associations of chromosome anomalies and cancer cell lines have been excluded. The preface contains seven tables, listing chromosome involved in polymorphisms, breakage, and aneuploidy syndro...

THE MAJORITY OF MALIGNANT CELLS PRESENT GENETIC INSTABILITY WITH CHROMOSOME NUMBER CHANGES PLUS SEGMENTAL DEFECTS: these changes involve intact chromosomes and breakage-induced alterations. Some pathways of chromosomal instability have been proposed as random breakage, telomere fusion, and centromere fission. Chromosome alterations in tumor cells have been described in animal models and in vitr...

Since trisomies produce adverse effects relatively late in development or even postnatally, they are an important component of the array of genetic damages that might be caused by environmental agents. Whole-chromosome aneuploidy (as opposed to breakage-derived aneuploidy) might come about secondarily from crossover depression, or could follow damage to the meiotic spindle or to kinetochores. F...

Gametocidal (Gc) chromosomes or elements in species such as Eig are preferentially transmitted to the next generation through both the male and female gametes when introduced into wheat ( L.). Furthermore, any genes, such as genes that control agronomically important traits, showing complete linkage with Gc elements, are also transmitted preferentially to the next generation without the need fo...

Convention terminology. There follows a compilation of numerical abnormalities of chromosome constitution, again in order 1 to 22, X and Y. There is a table of syndromes associated with breakage syndromes. Associations of chromosome anomalies and cancer cell lines have been excluded. The preface contains seven tables, listing chromosome involved in polymorphisms, breakage, and aneuploidy syndro...

We obtained strains of yeast with large segments of 2 mu plasmid DNA integrated at several chromosomal locations by selecting genetically for recombination between a chromosomal sequence carried on a 2 mu-circle-containing hybrid plasmid and a homologous sequence on the chromosome. In all diploids examined, the presence of 2 mu circle sequences causes a marked instability of the chromosome into...

Chromosomal translocations in lymphoid tumors frequently result from recombination between a normally rearranging antigen receptor gene and a normally non-rearranging second locus. The possibility that the lymphocyte recombinase apparatus plays a role in determining the position of breakage at the second locus has been a matter of controversy because of the inconsistent presence of heptamer-lik...

Benzene and formaldehyde (FA) are important industrial chemicals and environmental pollutants that cause leukemia by inducing DNA damage and chromosome aberrations in hematopoietic stem cells (HSC), the target cells for leukemia. Our previous studies showed that workers exposed to benzene and FA exhibit increased levels of aneuploidy in their blood cells. As centrosome amplification is a common...

The major mechanism for ring chromosome formation is thought to result from breakage and reunion at the breakpoints on the long and short arms of a chromosome. This fusion event can produce terminal arm inversions, deletions, and duplications that determine the resulting phenotype.[1] Ring chromosome 13 is relatively uncommon, with an estimated incidence of 1/58,000 live births. Clinical severi...