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?

Proceed order?

Export
  • 1
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A fast, reproducible and non-hazardous technique for non-isotopic DNA fingerprinting is presented. The method is based on digoxigenated oligonucleotides, which are specific for simple repetitive DNA sequences. The use of digoxigenin/ anti-digoxigenin detection avoids many drawbacks inherent in e.g. the biotin/streptavidin system which often causes a poor signal-to-background ratio. Synthesis and purification of digoxigenated oligonucleotides and their use in filter hybridization are described in detail. Hybridization patterns obtained with four different radioactively labeled oligonucleotides have been compared with those of the respective digoxigenated probes. When slightly less stringent hybridization conditions are applied for digoxigenated oligonucleotides than for those labeled with 32P, the signal intensities are satisfying but additional minor bands occur as a result of the reduced strigency. With one explainable exception, these bands increase the information content of the fingerprint. In addition, hybridization of the digoxigenated (CAC)5 probe has been performed in situ with human metaphase chromosomes. The hybridization patterns in many mitoses resemble R-bands.
    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 Tandemly organized simple repetitive sequences are widespread in all eukaryotes. The organization of the simple tetrameric (GACA)n sequences at chromosomal loci has been investigated using in situ hybridization with chemically pure oligonucleotide probes. Both biotin- and digoxigenin-attached (GACA)4 probes reveal specific hybridization signals over the short arms of all acrocentric autosomes in man. In the other examined primates the NOR-bearing autosomes could be detected by in situ hybridization with (GACA)4, and a major concentration of the GACA simple repeats could be observed on the Y chromosome in the gibbon and mouse; the hybridization site in the gibbon Y chromosome coincides particularly with the silver-stainable NOR. In the past, accumulations of (GACA)n sequences were demonstrated mainly on vertebrate sex chromosomes. Therefore, the organization of GACA simple sequences is discussed in the context of their evolutionary potential accumulation and the possible linkage with the primate rDNA loci.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Genomic organization and chromosomal localization of a previously uncharacterized D (Donor) locus in Xiphophorus and Poecilia species was investigated using fluorescence in situ hybridization (FISH) and Southern blot analysis. Part of this region is thought to be involved in the recombination event leading to formation of the Xmrk oncogene and it has recently been shown that this locus includes two different genes, one with high homology to a zinc finger protein of the Krüppel type, and the other an unknown gene with high similarity to a Caenorhabditis elegans gene. FISH to Xiphophorus chromosomes revealed that these two unrelated genes are closely linked and clustered at a unique chromosomal site. Southern blot hybridization patterns suggest that these genes exist in the genome as multiple copies. Furthermore, similar genomic organization profiles seem to prevail among other related fish. In particular, our FISH experiments reveal the existence of a conserved homologous chromosomal segment harboring the zinc finger protein sequence in several poeciliid fish.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Chromosoma 93 (1986), S. 367-374 
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The X and Y chromosomes of the musk shrew are the two largest in the complement and they regularly form a single chiasma during meiosis. This chiasma is located in the short arms of the X and Y, both of which show partial C-banding at meiosis. The in vitro incorporation of 5-bromodeoxyuridine/tritiated thymidine during late S reveals that the non-C-band region of the Y finishes replication later than the C-band positive heterochromatin. During meiosis, the sex bivalent opens out early in pachytene to reveal a single chiasma which persists until late metaphase-I. In surface-spread, silver-stained meiocytes, the sex bivalent morphology changes from a phase of extensive pairing to one which includes a visible chiasma through a brief diffuse stage. Observations on C-banded meiocytes show a shift in the sex pair from a C-band positive to a negative state as compared to their corresponding somatic pattern. Comparable changes are also observed in the sex bivalents of other mammals which undergo a chiasmatic exchange. This suggests that in addition to pairing homology, an alteration in the chromatin configuration may be necessary for crossing over to occur between the sex 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 The sex chromosomes of Microtus agrestis are extremely large due to the accumulation of constitutive heterochromatin. We have identified two prominent satellite bands of 2.0 and 2.8 kb in length after HaeIII and HinfI restriction enzyme digestion of genomic DNA, respectively. These satellites are located on the heterochromatic long arm of the X chromosome as shown using Microtus x mouse somatic cell hybrids. By in-gel hybridization with oligonucleotide probes, the organization of the two satellites was studied: among the many copies of the simple tandem tetranucleotide repeat GATA are interspersed rare single GACA tetramers. One of the satellites also harbours related GGAT simple tandem repeats. In situ hybridizations with plasmid-carried or oligonucleotide GA C T A probes show clustered silver grains on the long and short arm of the X chromosome. Interspersion of differently organized (GATA)n elements is also demonstrable in the autosomal complement and on the Y chromosome. These results are discussed in the context of the evolution of vertebrate sex chromosomes in relation to heterochromatin and simple repetitive DNA sequences.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The Amazon Molly fish, P. formosa, is an all-female gynoform15 that depends on sperm of males of related bisexual species, P. mexicana or P. latipinna, for gynogenesis, that is, the sperm is needed to trigger embryogenesis physiologically (reviewed in ref. 16). Eggs are formed without meiosis17, ...
    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 Animal sex chromosome evolution has started on different occasions with a homologous pair of autosomes leading to morphologically differentiated gonosomes. In contrast to other vertebrate classes, among fishes cytologically demonstrable sex chromosomes are rare. In reptiles, certain motifs of simple tandemly repeated DNA sequences like (gata)n/(gaca)m are associated with the constitutive heterochromatin of sex chromosomes. In this study a panel of simple repetitive sequence probes was hybridized to restriction enzyme digested genomic DNA of poeciliid fishes. Apparent male heterogamety previously established by genetic experiments in Poecilia reticulata (guppy) was correlated with male-specific hybridization using the (GACA)4 probe. The (GATA)4 oligonucleotide identifies certain male guppies by a Y chromosomal polymorphism in the outbred population. In contrast none of the genetically defined heterogametic situations in Xiphophorus could be verified consistently using the collection of simple repetitive sequence probes. Only individuals from particular populations produced sex-specific patterns of hybridization with (GATA)4. Additional poeciliid species (P. sphenops, P. velifera) harbour different sex-specifically organized simple repeat motifs. The observed sex-specific hybridization patterns were substantiated by banding analyses of the karyotypes and by in situ hybridization using the (GACA)4 probe.
    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. The Cdc7 kinase is required for the G1/S-phase transition during the cell cycle and plays a direct role in the activation of individual origins of replication in Saccharomyces cerevisiae. Here, we report the identification of a mouse cDNA, MmCdc7, whose product is closely related in sequence to Saccharomyces cerevisiae Cdc7 as well as their human, Xenopus and Schizosaccharomyces pombe homologues. The MmCdc7p contains the conserved subdomains common to all protein-serine/threonine kinases and three kinase inserts that are characteristic of members of the Cdc7 protein family. We have mapped the locus of the MmCdc7 gene to chromosome 5, band 5E. Conservation of structures among members of the Cdc7-related proteins suggests that these proteins play a key role in the regulation of DNA replication during the cell cycle in all eukaryotes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The multiple sex chromosome system, X1X2Y ♂/X1X1X2X2♀, in the small Indian mongoose, Herpestes auropunctatus, results from a translocation of a part of Y chromosome to an autosome. It is not possible to distinguish the autosome which harbours the Y chromosome element in the somatic complement. By employing the surface-spreading technique to prophase I meiocytes we have identified the region to which the Y chromosome has been translocated as the short arm of chromosome 9 which is a subtelocentric chromosome. This Y chromosome component lacks heterochromatin and no sex vesicle is organised during meiotic prophase. This suggests to us that Y heterochromatin in mammals may be required for the production of a sex vesicle.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1432-1432
    Keywords: Chromosomal sex determination ; Heterochromatin ; “Junk” DNA ; DNA fingerprinting ; Oligonucleotide hydridization in situ
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Hybridization of restriction enzymedigested genomic guppy (Poecilia reticulata, Poeciliidae) DNA with the oligonucleotide probe (GACA)4 revealed a male-specific simple tandem repeat locus, which defines the Y chromosome in outbred populations. The related (GATA)4 probe identifies certain males with the red color phenotype. In contrast only in two out of eight laboratory guppy strains was the typical (GACA)4 band observed. By specific staining of the constitutive heterochromatin one pair of chromosomes could also be identified as the sex chromosomes, confirming the XX/XY mechanism of sex determination. All males exhibit Y chromosomes with a large region of telomeric heterochromatin. Hybridization in situ with nonradioactively labeled oligonucleotide probes localized the (GACA)n repeats to this heterochromatic portion. Together these results may be regarded as a recent paradigm for the differentiation of heteromorphic sex chromosomes from a pair of autosomes during the course of evolution. According to the fish model system, this may have happened in several independent consecutive steps.
    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...