ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Information is presented which has been obtained from an exhaustive examination of 44 probands with a supernumerary marker chromosome (mar) and their families. The data include the derivation of the mar, frequency in various populations, inheritance and possible effect on fertility, congenital abnormality, and mental ability. The practical problems in assessing the risk of abnormality in a foetus discovered during prenatal diagnosis to be carrying a mar, are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary DiGeorge syndrome (DGS) is a human developmental defect of the structures derived from the third and fourth pharyngeal pouches. It apparently arises due to deletion of 22q11. We describe a strategy for the isolation of DNA probes for this region. A deleted chromosome 22, which includes 22q11, was flow-sorted from a lymphoblastoid cell line of a patient with cat eye syndrome and used as the source of DNA. A DNA library was constructed from this chromosome by cloning into the EcoR1 site of the vector Lambda gt10. Inserts were amplified by PCR and mapped using a somatic cell hybrid panel of this region. Out of 32 probes, 14 were mapped to 22q11. These probes were further sublocalised within the region by dosage analysis of DGS patients, and by the use of two new hybrid cell lines which we have produced from DGS patients. One of these lines (7939B662) contains the altered human chromosome segregated from its normal homologue. This chromosome 22 contains an interstitial deletion in 22q11, and will be useful for localising further probes to the DGS region.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary G- and R-banded chromosome preparations from eight of twelve 46,XX males, with no evidence of mosaicism or a free Y chromosome, were distinguished in blind trials from preparations from normal 46,XX females by virtue of heteromorphism of the short arm of one X chromosome. Photographic measurements on X chromosomes and on chromosome pair 7 in cells from twelve 46,XX males, eight 46,XX females, and four 46,XY males revealed a significant increase in the size of the p arm of one X chromosome in the group of XX males, independently characterised as being heteromorphic for Xp. No such differences were observed between X chromosomes of normal males and females or between homologues of chromosome pair 7 in all groups. The heteromorphism in XX males is a consequence of an alteration in shape (banding profile) and length of the tip of the short arm of one X chromosome, and the difference in size of the two Xp arms in these 46,XXp+ males ranged from 0.4% to 22.9%. From various considerations, including the demonstration of a Y-specific DNA fragment in DNA digests from nuclei of one of three XX males tested, it is concluded that the Xp+ chromosome is a product of Xp-Yp exchange. These exchanges are assumed to originate at meiosis in the male parent and may involve an exchange of different amounts of material. The consequences of such unequal exchange are considered in terms of the inheritance of genes located on Yp and distal Xp. No obvious phenotypic difference was associated with the presence or absence of Xp+. Thus, some males diagnosed as 46,XX are mosaic for a cryptic Y-containing cell line, and there is now excellent evidence that maleness in others may be a consequence of an autosomal recessive gene. The present data imply that in around 70% of 46,XX males, maleness is a consequence of the inheritance of a paternal X-Y interchange product.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Frequency distributions of fluorescence intensity of ethidium bromide stained human chromosomes from nine phenotypically normal males are cross correlated and autocorrelated following repeated flow cytometric measurements. It is shown that each individual donor produces a fluorescence profile which is both visually and numerically different from those of other individuals in the set. The wide variety of chromosome heteromorphisms which occur to varying degrees for chromosomes 1, 9, 13, 14, 15, 16, 21, 22 and Y give rise to the uniqueness of a given fluorescence profile. Estimates of chromosome heteromorphisms for each individual in the set were made and then compared with parallel results obtained from inspection of Q-banded and C-banded conventional metaphase preparations. Fluorescence profiles identifiable with each individual were also obtained for Hoechst 33258 stained chromosomes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Peripheral blood lymphocyte metaphase chromosomes of three Bovoidean species have been studied using Quinacrine fluorescence and Giemsa banding techniques to give Q-, G-, and C-banding patterns. Q- and G-banding characteristics, coupled with chromosome length, enabled all of the chromosomes in each of the chromosome complements to be clearly distinguished, although some difficulties were encountered with the very smallest chromosomes. A comparison of G-banding patterns between the species revealed a remarkable degree of homology of banding patterns. Each of the 23 different acrocentric autosomes of the domestic sheep (2n=54) was represented by an identical chromosome in the goat (2n=60) and the arms of the 3 pairs of sheep metacentric autosomes were identical matches with the remaining 6 goat acrocentrics. A similar interspecies homology was evident for all but two of the autosomes in the ox (2n=60). This homology between sheep metacentric and goat acrocentric elements confirms a previously suggested Robertsonian variation. The close homology in G-banding patterns between these related species indicates that the banding patterns are evolutionarily conservative and may be a useful guide in assessing interspecific relationships. —The centromeric heterochromatin in the autosomes of the three species was found to show little or no Q-or G-staining, in contrast to the sex chromosomes. This lack of centromeric staining with the G-technique (ASG) contrasts markedly with results obtained with other mammalian species. However, with the C-banding technique these regions show a normal intense Giemsa stain and the C-bands in the sex chromosomes are inconspicuous. The amount of centromeric heterochromatin in the sheep metacentric chromosomes is considerable less than in the acrocentric autosomes or in a newly derived metacentric element discovered in a goat. It is suggested that the pale G-staining of the centromeric heterochromatin in these species might be related to the presence of G-Crich satellite DNA.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The similarities and differences between the banding patterns obtained in human chromosomes with the Quinacrine fluorescence and the Acetic-Saline-Giemsa (ASG) techniques are described. The use of these techniques to identify each chromosome pair in the human karyotype is discussed, as also is the use of the methods to identify aberrant chromosomes and to map points of exchange in translocations and inversions. A number of examples are used to illustrate the resolution permitted by these new methods. Seven polymorphic regions on normal chromosomes are described, which include four identified by fluorescence on chromosomes 3,4, 13, and 22. The secondary constrictions on chromosomes 1, 9, and 16, which had previously been observed in conventionally stained preparations from favourable material, are particularly clear in all cells treated with the Giemsa techniques. The new methods make it possible to detect small differences in size between the heterochromatic blocks at these regions in homologous chromosomes. The benefit to human genetics of studying the familial segregation of both structurally rearranged and normal, but polymorphic chromosomes, where the chromosomes or parts of chromosomes can be unambiguously identified is stressed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Cultured human peripheral blood lymphocytes were labelled with 3H-thymidine in the early or late S phase prior to mitosis. Quinacrine fluorescence patterns in metaphase chromosomes were then recorded photographically and the slides reprocessed for autoradiography so that the same metaphase cells were examined with the two techniques. The intensity and distribution of 3H-thymidine labelling was compared with the intensity and distribution of Q fluorescence with particular reference to chromosomes 1, 13, 14, 15, 17, 18, 19, 20, 21 and 22. It was found that chromosome regions showing bright fluorescence were also late replicating and that, in general, patterns of late replications reflected the patterns of fluorescence. Exceptions to this generalisation included the late labelling X chromosome in cells of female origin and areas near the centromeres on chromosomes 1, 9, 16 and 22. These centromeric regions show a dull fluorescence but, with exception of chromosome 9, are strongly Giemsa-positive in the ASG staining technique. On the basis of staining reaction, late replicating heterochromatic regions fall into five categories, the relationships and functional significance of these categories is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract 3H-rRNA obtained from Xenopus laevis tissue cultured cells, or a 3H-cRNA made from Xenopus ribosomal DNA, was used for heterologous in situ hybridisation with human lymphocyte metaphase chromosomes. Prior to hybridisation, chromosome spreads were stained with Quinacrine and selected cells showing good Q-banding photographed; the same cells were then rephotographed after autoradiography and pairs of photographs for each cell were used to make dual karyotypes. The chromosomes within each karyotype were divided into equal sized segments (approx. 0.7 μ), with a fixed number of segments for each chromosome type. The distribution of silver grains between segments showed that the 3H-RNAs hybridised specifically to the nucleolar organising regions of the D and G group chromosomes with no other sites of localised labelling in the complement. Control experiments showed no localisation, with insignificant labelling, when metaphase spreads were incubated in a mixture containing Xenopus 3H-rRNA and competing cold human (HeLa) rRNA. Filter hybridisation experiments on isolated human DNA showed that the Xenopus derived 3H-RNAs hybridised to a fraction of human DNA which was on the heavy side of the main DNA peak and that these RNAs were competed out in the presence of excess cold human rRNA, confirming the specificity of the heterologous hybridisation. In situ hybridisation experiments were also carried out on cells from individuals with one chromosome pair showing heteromorphism for either a very long stalk (nucleolar constriction) subtending a satellite, or a large satellite. It was shown that the chromosome with the large stalk hybridised four times as much 3H-rRNA as its homologue, whereas differences in the sizes of the subtended satellites did not materially affect hybridisation levels indicating that rDNA is located in the stalks and not the satellites. The amount of 3H-rRNA hybridised differs between chromosomes and individuals; these differences are heritable and rDNA can be detected by in situ hybridisation in all three chromosomes number 21 in cells from Down's patients and in translocated chromosomes conta.ining a nucleolar constriction. Different D and G group chromosomes which hybridised equal amounts of 3H-rRNA participated in rosette associations at metaphase in a random fashion in some individuals and in a non-random fashion in others. In all individuals studied chromosomes with large amounts of rDNA were not found to be preferentially involved in association. It was therefore concluded that the probability of a chromosome being involved in the formation of a common nucleolus is not a simple function of its rDNA content and other possible factors are considered.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Chromosoma 10 (1959), S. 115-135 
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. The number of nuclei found in the hyphal cells was found to vary between 1 and 36, with a mean at 6.44±0.08. In contrast with this variability the cells of the hymenium were always found to be initially binucleate. This reduction in nuclear number in the hymenial tissue is attributed to a number of factors. 2. Evidence for the heterozygous nature of the fusion nucleus was obtained from a study of chromosome bridges at Anaphase I and II of meiosis. This accords with the genetical results of other investigators who have shown that segregation of a number of factors occurs at meiosis. 3. Clamp connections and conjugate mitotic spindles were not observed although nuclear migration between cells was found to occur. It is suggested that this migration may provide an opportunity for maintaining a genetic balance between cells. 4. It was found that the resting nuclei could attain one of two resting conditions, the expanded or the homogeneous state, which were characterised by differences in staining affinity. It was shown that the different resting states were not the result of genetical differences between nuclei and did not represent different stages of the mitotic cycle. From observations on the development of the young basidium and on the distribution of these two nuclear types, it is suggested that the difference between the resting nuclei is primarily associated with a difference in cellular activity, the homogeneous resting nuclei characterising cells in active metabolic states. 5. The haploid chromosome number was found to be n = 12, a determination which differs from previously recorded numbers, and the 24 chromosomes of the fusion nucleus regularly formed 12 bivalents at meiosis. The presence of laggard chromosomes at meiosis and mitosis was attributed to sticky adhesions between heterochromatic regions of the chromosomes. 6. Contrary to the reports of previous investigators, centrosomes were not observed at meiosis or mitosis. Observations made on other Basidiomycetes and reports by other investigators suggest that the absence of centrosomes may be a characteristic of the group. 7. Differences in the manner of alignment of the spindles at the second division of meiosis were found between basidia. It was shown that the nuclear constitution of the basidiospores depended upon the type of spindle alignment, and a bias towards the production of spores containing non-sister nuclei was found. It is pointed out that the production of an excess of spores containing non-sister nuclei serves to maintain a high degree of heterokaryosis without involving nuclear exchange between plants.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 42 (1986), S. 1069-1075 
    ISSN: 1420-9071
    Keywords: Mapping ; linkages ; mutant alleles ; antenatal diagnosis ; genetic therapy ; genetics and cancer ; mutagenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...