Search results for "Romer"
showing 10 items of 86 documents
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 …
Genetic manipulation of HSP26 and YHR087W stress genes may improve fermentative behaviour in wine yeasts under vinification conditions
2008
Throughout wine production yeast cells are affected by a plethora of stress conditions that compromise their ability to carry out the whole process. In recent years important knowledge about the mechanisms involved in stress response in both laboratory and wine yeast strains has been obtained. Several studies have indicated that a correlation exists between stress resistance, expression of stress response genes and fermentative behaviour. In this work we introduce several genetic manipulations in two genes induced by several stress conditions: HSP26 (which encodes a heat shock protein) and YHR087W (encoding a protein of unknown function) in two different wine yeasts, ICV16 and ICV27. These …
Brief communication. Karyotype analysis, banding, and fluorescent in situ hybridization in the scarab beetle Gymnopleurus sturmi McLeay (Coleoptera S…
2000
Conventional staining, differential banding, and in situ hybridization with both ribosomal and telomeric probes to mitotic chromosomes of Gymnopleurus sturmi (Scarabaeoidea : Scarabaeidae) are described. The karyotype is distinguished by a pericentric inversion polymorphism in chromosome 3, which is either acrocentric or subtelocentric. Silver staining (Ag-NOR) and chromomycin A3 (CMA3), failed to study the detection of nucleolar organizer regions (NORs), due to the extensive silver and CMA3 stainability of all GC-rich heterochromatin. Fluorescent in situ hybridization (FISH) using a Paracentrotus lividus (Echinodermata) rDNA probe mapped the ribosomal RNA genes (rDNA). FISH with the all-hu…
CENPA overexpression promotes genome instability in pRb-depleted human cells
2009
Abstract Background Aneuploidy is a hallmark of most human cancers that arises as a consequence of chromosomal instability and it is frequently associated with centrosome amplification. Functional inactivation of the Retinoblastoma protein (pRb) has been indicated as a cause promoting chromosomal instability as well centrosome amplification. However, the underlying molecular mechanism still remains to be clarified. Results Here we show that pRb depletion both in wild type and p53 knockout HCT116 cells was associated with the presence of multipolar spindles, anaphase bridges, lagging chromosomes and micronuclei harbouring whole chromosomes. In addition aneuploidy caused by pRb acute loss was…