• MeSH
• chromozomální aberace diagnóza   MeSH
• distamyciny diagnostické užití   MeSH
• fenotyp MeSH
• finanční podpora výzkumu jako téma MeSH
• hodnocení rizik MeSH
• karyotypizace metody   normy   trendy   MeSH
• lidé MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• přehledy MeSH

• MeSH
• chromozomální aberace MeSH
• genetické markery MeSH
• genetika MeSH
• lidské chromozomy MeSH

• NLK Obory
• biologie
• genetika, lékařská genetika

• MeSH
• Acanthocephala genetika   izolace a purifikace   MeSH
• chromozomální aberace MeSH
• chromozomy ultrastruktura   MeSH
• karyotypizace MeSH
• nemoci ryb parazitologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH

• MeSH
• chromozomální poruchy diagnóza   MeSH
• cytogenetika MeSH
• Downův syndrom MeSH
• histologické techniky MeSH
• novorozenec MeSH
• Check Tag
• novorozenec MeSH

We identified a small, paternally inherited, supernumerary marker chromosome, inv dup(15), in a phenotypically normal and normozoospermic male from a couple with reproductive problems. Sperm analysis by fluorescence in situ hybridization (FISH) showed that the marker was present in 26% of sperm nuclei. The disomy 15 was 10 times higher than in normal control donors. FISH analysis for aneuploidies of the other chromosomes showed an increase in nondisjunction of chromosome 21. We also examined 24 embryos by preimplantation genetic diagnosis, and 10 embryos (41.7%) contained the marker. This report provides information about inheritance of inv dup(15) from a male carrier.

• MeSH
• dospělí MeSH
• embryo savčí MeSH
• heterozygot MeSH
• hybridizace in situ fluorescenční MeSH
• lidé MeSH
• lidské chromozomy, pár 15 * genetika   MeSH
• mužská infertilita * genetika   MeSH
• rodokmen MeSH
• spermie * MeSH
• těhotenství MeSH
• uniparentální disomie * genetika   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• Publikační typ
• kazuistiky MeSH
• práce podpořená grantem MeSH

Sex chromosomes are generally derived from a pair of classical type-A chromosomes, and relatively few alternative models have been proposed up to now.1,2 B chromosomes (Bs) are supernumerary and dispensable chromosomes with non-Mendelian inheritance found in many plant and animal species3,4 that have often been considered as selfish genetic elements that behave as genome parasites.5,6 The observation that in some species Bs can be either restricted or predominant in one sex7-14 raised the interesting hypothesis that Bs could play a role in sex determination.15 The characterization of putative B master sex-determining (MSD) genes, however, has not yet been provided to support this hypothesis. Here, in Astyanax mexicanus cavefish originating from Pachón cave, we show that Bs are strongly male predominant. Based on a high-quality genome assembly of a B-carrying male, we characterized the Pachón cavefish B sequence and found that it contains two duplicated loci of the putative MSD gene growth differentiation factor 6b (gdf6b). Supporting its role as an MSD gene, we found that the Pachón cavefish gdf6b gene is expressed specifically in differentiating male gonads, and that its knockout induces male-to-female sex reversal in B-carrying males. This demonstrates that gdf6b is necessary for triggering male sex determination in Pachón cavefish. Altogether these results bring multiple and independent lines of evidence supporting the conclusion that the Pachón cavefish B is a "B-sex" chromosome that contains duplicated copies of the gdf6b gene, which can promote male sex determination in this species.

• MeSH
• biologická evoluce MeSH
• Characidae * genetika   MeSH
• jeskyně MeSH
• pohlavní chromozomy genetika   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Background: Cytogenetically visible chromosomal imbalances in humans are deleterious and adverse in the majority of the cases. However, healthy persons living with chromosomal imbalances in the range of several megabasepairs (Mbps) in size, like carriers of small Supernumerary Marker Chromosomes (sSMCs) exist. Materials & Methods: The identification of healthy sSMC carriers with euchromatic centromere-near (ECN) imbalances led to the following proposal: ECN-regions do not contain any dosage sensitive genes. Due to own previous work, dosage-insensitive pericentric ECN-regions were already determined with an accuracy of 0.3 and 5 Mbp. Based on this data we established 43 new pericentromeric probe sets spanning about 3-5 Mbp of each euchromatic human chromosome arm starting from the known insensitive regions towards distal. Such so called pericentromeric-critical region fluorescence in situ hybridization (PeCR-FISH) probe sets were applied exemplarily and successful here in 15 sSMC cases as available from the Else Kröner-Fresenius-sSMC-cellbank . Conclusion: Most of the involved sSMC breakpoints could be characterized as a higher resolution than before. An unexpected result was that in 5/15 cases cryptic mosaicism was characterized. The latter is also to be considered to have potentially an influence on the clinical outcome in these so-called discontinuous sSMCs. Overall, the suitability of PeCR-FISH to characterize sSMCs was proven; the potential of this probe set to further delineate sizes of dosage insensitive pericentric regions is obvious but dependent on suited cases. Furthermore, discontinuous sSMCs can be identified by this approach and this new subtype of sSMC needs to be studied in more detail in future.

• Publikační typ
• časopisecké články MeSH

BACKGROUND: B chromosomes are supernumerary dispensable parts of the karyotype which appear in some individuals of some populations in some species. Often, they have been considered as 'junk DNA' or genomic parasites without functional genes. SCOPE OF REVIEW: Due to recent advances in sequencing technologies, it became possible to investigate their DNA composition, transcriptional activity and effects on the host transcriptome profile in detail. Here, we review the most recent findings regarding the gene content of B chromosomes and their transcriptional activities and discuss these findings in the context of comparable biological phenomena, like sex chromosomes, aneuploidy and pseudogenes. MAJOR CONCLUSIONS: Recent data suggest that B chromosomes carry transcriptionally active genic sequences which could affect the transcriptome profile of their host genome. GENERAL SIGNIFICANCE: These findings are gradually changing our view that B chromosomes are solely genetically inert selfish elements without any functional genes. This at one side could partly explain the deleterious effects which are associated with their presence. On the other hand it makes B chromosome a nice model for studying regulatory mechanisms of duplicated genes and their evolutionary consequences.

• MeSH
• chromozomy genetika   MeSH
• Eukaryota genetika   MeSH
• genetická transkripce * MeSH
• genom MeSH
• hybridizace in situ fluorescenční MeSH
• intergenová DNA genetika   MeSH
• lidé MeSH
• molekulární evoluce * MeSH
• pseudogeny genetika   MeSH
• regulace genové exprese genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

B chromosomes (Bs) are supernumerary chromosomes, which are often preferentially inherited. When transmission rates of chromosomes are higher than 0.5, not obeying the Mendelian law of equal segregation, the resulting transmission advantage is collectively referred to as 'chromosome drive'. Here we analysed the drive mechanism of Aegilops speltoides Bs. The repeat AesTR-183 of A. speltoides Bs, which also can be detected on the Bs of Aegilops mutica and rye, was used to track Bs during pollen development. Nondisjunction of CENH3-positive, tubulin interacting B sister chromatids and an asymmetric spindle during first pollen grain mitosis are key for the accumulation process. A quantitative flow cytometric approach revealed that, independent of the number of Bs present in the mother plant, Bs accumulate in the generative nuclei to > 93%. Nine out of 11 tested (peri)centromeric repeats were shared by A and B chromosomes. Our findings provide new insights into the process of chromosome drive. Quantitative flow cytometry is a useful and reliable method to study the drive frequency of Bs. Nondisjunction and unequal spindle organization accompany during first pollen mitosis the drive of A. speltoides Bs. The prerequisites for the drive process seems to be common in Poaceae.

• MeSH
• Aegilops genetika   MeSH
• aparát dělícího vřeténka metabolismus   MeSH
• buněčné jádro genetika   MeSH
• centromera metabolismus   MeSH
• chromozomy rostlin genetika   MeSH
• konzervovaná sekvence genetika   MeSH
• mitóza genetika   MeSH
• nondisjunkce genetická * MeSH
• pyl genetika   MeSH
• repetitivní sekvence nukleových kyselin genetika   MeSH
• sekvence nukleotidů MeSH
• žito genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Chromosomal instability evoked by abnormalities in centrosome numbers has been traditionally considered as a hallmark of aberrant, typically cancerous or senescent cells. We have reported previously that pristine human embryonic stem cells (hESC) suffer from high frequency of supernumerary centrosomes and hence may be prone to undergo abnormal mitotic divisions. We have also unraveled that this phenomenon of multicentrosomal mitoses vanishes with prolonged time in culture and with initiation of differentiation, and it is strongly affected by the culture substratum. In this study, we report for the first time that Cripto-1 protein (teratocarcinoma-derived growth factor 1, epidermal growth factor-Cripto/FRL-1/Cryptic) produced by hESC represents a factor capable of inducing formation of supernumerary centrosomes in cultured hESC. Elimination of Cripto-1 signaling on the other hand restores the normal number of centrosomes in hESC. Linking the secretory phenotype of hESC to the centrosomal metabolism may help to develop better strategies for propagation of stable and safe bioindustrial and clinical grade cultures of hESC. From a broader point of view, it may lead to unravelling Cripto-1 as a micro-environmental factor contributing to adverse cell behaviors in vivo.

• MeSH
• buněčná diferenciace genetika   MeSH
• centrozom * MeSH
• GPI-vázané proteiny antagonisté a inhibitory   genetika   MeSH
• lidé MeSH
• lidské embryonální kmenové buňky cytologie   metabolismus   MeSH
• mezibuněčné signální peptidy a proteiny genetika   MeSH
• mitóza genetika   MeSH
• nádorové proteiny antagonisté a inhibitory   genetika   MeSH
• signální transdukce genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH