introduction: fluorscence in situ hybridization (fish) enables specific detection of unique sequences of varying length, chromosomal regions or entire chromosomes within metaphase or interphase cells. recent developments in this technology permit the rapid mapping and ordering of dna fragments on single metaphase chromosome bands. the technique of fish incorporates several stages including: pro...

1. The purpose of the in vitro chromosome aberration test is to identify agents that cause structural chromosome aberrations in cultured mammalian cells (1)(2)(3). Structural aberrations may be of two types, chromosome or chromatid. With the majority of chemical mutagens, induced aberrations are of the chromatid type, but chromosome-type aberrations also occur. An increase in polyploidy may ind...

We have studied somatic cell hybrids between P3x63Ag8 mouse myeloma cells deficient in hypoxanthine phosphoribosyltransferase (EC 2.4.2.8) and either human peripheral lymphocytes or human lymphoblastoid or myeloma cells for the production of human immunoglobulin chains and for the expression of enzyme markers assigned to each of the different human chromosomes. Human chromosome 14 was the only ...

The mammalian protooncogene homologue of the avian v-ets sequence from the E26 retrovirus consists of two sequentially distinct domains located on different chromosomes. Using somatic cell hybrid panels, we have mapped the mammalian homologue of the 5' v-ets-domain to chromosome 11 (ETS1) in man, to chromosome 9 (Ets-1) in mouse, and to chromosome D1 (ETS1) in the domestic cat. The mammalian ho...

Loss of heterozygosity is a significant oncogenetic mechanism and can involve a variety of mechanisms including chromosome loss, deletion, and homologous interchromosomal mitotic recombination. Analysis of H-2 antigen-loss variants from heterozygous murine cell lines provides an experimental system to estimate the relative contributions of different mechanisms for allele loss and to compare the...

Cleavage in Cecidomyidae (Diptera) is characterized by the elimination of chromosomes from presumptive somatic nuclei. The full chromosome complement is kept by the germ-line nuclei. The course of cleavage in Mayetiola destructor (Say) is described. After the fourth division two nuclei lie in the posterior polar-plasm and become associated with polar granules, and fourteen nuclei lie in the res...

Children with neurofibromatosis type 1 (NF-1), being constitutionally deficient for one allele of the NF1 gene, are at greatly increased risk of juvenile myelomonocytic leukemia (JMML). NF1 is a negative regulator of RAS pathway activity, which has a central role in JMML. To further clarify the role of biallelic NF1 gene inactivation in the pathogenesis of JMML, we investigated the somatic NF1 ...

Trifolium species and cultivars are considered important forage crops iran , growing throughout the country. The present article considered the karyotypic details of Trvulim taxa using multivariate statistical analysis. Taxa studied included: Trifolim restylinatum (six populations: Shazand, Soriyan, Kordestan, Harati, Enaj and Lordegan), T. repense, T, fragverm, T. prateme and T, alexandrin...

In cultivated tomato plants which were largely but not exclusively derived from triploids, chromosomes of two distinct sizes were found associated with the nucleolus in the pollen mother cells. Since a trivalent was found on the nucleolus in the simple trisomic type, triplo-A only, evidently it is the A or first chromosome which is dimorphic. At somatic metaphase this chromosome has a distinct ...

Programmed chromosome breakage occurs at 50-200 specific sites in the genome of Tetrahymena thermo-phila during somatic nuclear (macronuclear) differentiation. Previous studies have identified a 15 bp sequence, the Cbs (for chromosome breakage sequence), that is necessary and sufficient to specify these sites. In this study we determined the effects of mutations in the Cbs on its ability to spe...