Search results for "Centromere"
showing 10 items of 35 documents
Treatment with the anti-tumor drugs, cis-platin and mafosfamide, does not affect the structure of prekinetochores in a human breast cancer cell line.…
1996
Abstract The goal of the present article was to determine whether a nuclear parameter, centromere structure of interphase cells, could serve as an indicator to assess cellular damage caused by anti-tumor drugs. These were cis-platin and mafosfamide, which are widely used for the management of solid tumors. To visualize the centromeres, we probed treated and untreated cells of a human breast cancer cell line, MX-1, with a human anti-centromere serum. The serum was obtained from a scleroderma patient and detects antigens associated with prekinetochores of the decondensed chromosomes. The DNA was simultaneously displayed by a specific fluorescent dye. The cells were grown on coverslips, incuba…
Eight million years of maintained heterozygosity in chromosome homologs of cercopithecine monkeys
2020
In the Cercopithecini ancestor two chromosomes, homologous to human chromosomes 20 and 21, fused to form the Cercopithecini specific 20/21 association. In some individuals from the genus Cercopithecus, this association was shown to be polymorphic for the position of the centromere, suggesting centromere repositioning events. We set out to test this hypothesis by defining the evolutionary history of the 20/21 association in four Cercopithecini species from three different genera. The marker order of the various 20/21 associations was established using molecular cytogenetic techniques, including an array of more than 100 BACs. We discovered that five different forms of the 20/21 association w…
Sequence and analysis of chromosome 3 of the plant Arabidopsis thaliana.
2000
Arabidopsis thaliana is an important model system for plant biologists. In 1996 an international collaboration (the Arabidopsis Genome Initiative) was formed to sequence the whole genome of Arabidopsis and in 1999 the sequence of the first two chromosomes was reported. The sequence of the last three chromosomes and an analysis of the whole genome are reported in this issue. Here we present the sequence of chromosome 3, organized into four sequence segments (contigs). The two largest (13.5 and 9.2 Mb) correspond to the top (long) and the bottom (short) arms of chromosome 3, and the two small contigs are located in the genetically defined centromere. This chromosome encodes 5,220 of the rough…
Tetrasomy 18p de novo: Identification by FISH with conventional and microdissection probes and analysis of parental origin and formation by short seq…
1996
We report a de novo supernumerary isochromosome 18p in a child with tetrasomy 18p, analyzed by a straightforward combination of cytogenetic and molecular cytogenetic methods. The diagnostic procedure consisted of standard banding techniques and fluorescence in situ hybridization (FISH) with centromere and library DNA probes for chromosome 18, and 18p-specific FISH probes prepared by chromosome microdissection and in vitro amplification. The maternal origin as well as the most probable cell stages of formation of the supernumerary isochromosome were determined by typing of short sequence repeats (SSRs). The pattern of allelic distribution suggests a nondisjunction during meiosis followed by …
Mapping of Friedreich's ataxia locus by identification of recombination events in patients homozygous by descent
1994
The Friedreich's ataxia locus (FRDA) maps on chromosome 9q13. Genetic data, obtained from a small number of recombination events, indicated that the FRDA locus might be located centromeric to the D9S15/D9S5 linkage group, the most probable order being cen-FRDA-D9S5-D9S111-D9S15-D9S110-qter. Recently, new centromeric markers have been reported. Analysis of these markers allowed us to localize the recombination breakpoint in some of the recombinant families. However, only one proximal recombination has been found with these markers. To increase the genetic information from FRDA families, we have analyzed the centromeric markers FR1, FR2, FR7, FR8, and FR5 in patients homozygous by descent. Th…
Pseudo-exclusion from paternity due to maternal uniparental disomy 16.
1998
The investigation of a case of disputed paternity revealed indirect exclusion of the alleged father in the haptoglobin system and in the DNA single-locus system D16S309/Hinf I (MS205). The paternity index for the non-exclusion systems was > 10(6). Since both exclusion systems (HP and MS205) are located on chromosome 16, we investigated 10 microsatellite loci covering this chromosome with 10-20 cM resolution. Analysis of the child's chromosome showed only alleles of maternal origin and lack of inheritance of paternal alleles for five informative loci. The markers close to the centromere of chromosome 16 were heterozygous, whereas distal loci were either heterozygous or homozygous for materna…
The evolution of human synteny 4 by mapping sub-chromosomal specific probes in Primates
2014
Comparative cytogenetic data concerning the orthologue to human chromosome 4 in primates shows that this chromosome is conserved between humans and non-human primates. However, the degree of conservation is not as high as previously estimated. In primates it is as a rule a large submetacentric chromosome but many exceptions are known especially in taxa characterized by a high level of chromosomal rearrangements. The rearrangements that have been visualized by chromosome painting so far, which are mostly interchromosomal changes, are in fact only a fraction of the actual chromosomal changes that have occurred during evolution. Intrachromosome changes can be analysed through classical cytogen…
Centromere-Like Elements in Megaselia Spiracularis (Diptera: Phoridae): A Fine-Structure and Cytogenetic Study
2004
The present study was concerned with the karyotype of a humpbacked fly, Megaselia spiracularis (Diptera: Phoridae). Chromosome preparations of neuroblasts isolated from male and female pupae uniformly showed two pairs of metacentric chromosomes and a telocentric chromosome pair. All chromosomes were homomorphic. The analysis of ultrathin serial sections through spermatogonia in metaphase using transmission electron microscopy, confirmed the presence of 3 regular chromosome pairs. In ultrathin sections, the centromeres could be detected as individual elements owing to their lesser electron density in comparison with the chromosome arms. In addition, the spindles contained two tiny elements s…
Linker histone H1 is essential for Drosophila development, the establishment of pericentric heterochromatin, and a normal polytene chromosome structu…
2009
We generated mutant alleles of Drosophila melanogaster in which expression of the linker histone H1 can be down-regulated over a wide range by RNAi. When the H1 protein level is reduced to ∼20% of the level in wild-type larvae, lethality occurs in the late larval – pupal stages of development. Here we show that H1 has an important function in gene regulation within or near heterochromatin. It is a strong dominant suppressor of position effect variegation (PEV). Similar to other suppressors of PEV, H1 is simultaneously involved in both the repression of euchromatic genes brought to the vicinity of pericentric heterochromatin and the activation of heterochromatic genes that depend on their pe…
Chromosomal studies of five tropical scorpaeniform fishes (Teleostei, Scorpaenidae)
2003
Abstract The karyotypes of five species of Scorpaenidae (genera Scorpenopsis, Dendrochirus and Pterois) from the Indian Ocean were analysed using various banding methods and in situ hybridisation with a ribosomal probe. All the species investigated are characterised by a diploid set of 48 chromosomes (mainly acrocentric and/or subtelocentric) and by a NOR location on the small arm of a medium‐sized pair. All the chromosomes stained uniformly with DAPI, whereas C‐banding evidenced a small amount of hete‐rochromatin. Despite the marked morphological differences among these species, the low degree of diversification of the chromosome sets with respect to the ancestral set of teleosts (2n = 48 …