constitution was undertaken. L1210/Mes. has a tetraploid modal chromosome number, the chromosomes of which resemble, although in increased quantity, those of the original LI210 lymphoma of the mouse. However, a new marker chromosome, a long, biarmed dicentric, appeared in 8.6% of the L1210/Mes. cells examined. L1210/Mes. is capable of back-transfer in BDP! mice, where a gradual shift in stemlin...

ING chromosomes are potentially useful for studying the process of rejoining R after chromosome breakage, since a certain portion of the restitutions should produce dicentric ring chromosomes or interlocked rings rather than structurally normal chromosomes. The relevance of ring chromosomes studies to problems of induced chromosome breakage in Drosophila melanogaster sperm has been recognized f...

It has long been known that rearrangements of chromosomes through breakage-fusion-bridge (BFB) cycles may cause variability of phenotypic and genetic traits within a cell population. Because intercellular heterogeneity is often found in neoplastic tissues, we investigated the occurrence of BFB events in human solid tumors. Evidence of frequent BFB events was found in malignancies that showed un...

Armendares, S., Buentello, L., Salamanca, F., and Cantu-Garza, J. M. (1972). A dicentric Y chromosome without evidence of sex chromosomal mosaicism, 46,XYqdic, in a patient with features of Turner's syndrome. Journal of Medical Genetics, 9, 96-100. Caspersson, T., Lomakka, G., and Zech, L. (1971). The 24 fluorescence patterns of the human metaphase chromosomes-distinguishing characters and vari...

Large chromosomal events such as translocations and segmental duplications enable rapid adaptation to new environments. Here we marshal genomic, genetic, meiotic mapping, and physical evidence to demonstrate that a chromosomal translocation and segmental duplication occurred during construction of a congenic strain pair in the fungal human pathogen Cryptococcus neoformans. Two chromosomes under...

Biological dosimetry, based on the analysis of dicentric chromosomes, is an internationally established, independent method applied in the area of radiation protection. The biodosimetry is mainly performed, in addition to physical dosimetry, with the aim of individual dose assessment, especially after unclear or suspected radiation dose exposures. However, a new biodosimetrical challenge has em...

Somatic chromosome spreads from maize (Zea mays L.) plants containing B-A translocation chromosomes undergoing the chromosome type breakage-fusion-bridge cycle were examined by FISH. The size and type of extra chromosomes varied among cells of the same individual. A collection of minichromosomes derived from the chromosome type breakage-fusion-bridge cycle was examined for the presence of stabl...

Chromosomes of 39 healthy family members (3 generations from 13 families) living both in the high-level background radiation areas (HBRA) and the control areas (CA) were studied. Cumulative dose from birth to the time of blood sampling was estimated by calculating measured exposure rate in each individual. The cumulative doses ranged 30.9-358.9 and 6.0-59.2 mGy for HBRA and CA, respectively. Pe...

We wish to report a trisomy 21 child with two supernumerary fragments, whose mother had possibly related transient chromosome aberrations. The proband was an 8-year-old boy with typical features of Down's syndrome. The lymphocyte chromosomes studied at the ages of 3-5 months and 8 years showed a mosaic karyotype with both cell lines with trisomy 21 and one line (52% of the cells) with two addit...

Pericentric inversion of the secondary constriction region (qh) of human chromosome 9 is a frequent occurrence. This structural alteration is regarded as a normal familial variant, termed heteromorphism, and is inherited in a Mendelian fashion without any apparent phenotypic consequences. We characterized the qh region of chromosome 9 from five individuals using a series of molecular cytogeneti...