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  • 1
    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
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  • 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
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  • 3
    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
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  • 4
    ISSN: 1573-3297
    Keywords: Poeciliid fish ; male size polymorphism ; reproductive success
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract The male-polymorphic poeciliid fish,Limia perugiae, a small teleostean endemic to the southeast of the Caribbean island Hispañola, consists of three male size morphs with uniform females. Large males differentiate at a size varying between 25 and 38 mm; intermediate males, between 21 and 25 mm. Under competition, large males exhibit an elaborate courship display, whereas small males show only a sneak-chase behavior. Intermediate males adapt their tactics to the respective competitors. However, all male morphs can switch from courtship display to sneak-chase behavior. In large mating groups with four males of different size and five or six virgin females, large dominant α-males as well as small subordinate δ-males did not produce any offspring. Unexpectedly, all progeny were sired exclusively by the intemediate subordinate β- and γ-males. Breeding experiments with the three male morphs can best be explained by a model of Y-linked genes for small and large size which are both suspended by the activity of an autosomal recessive repressor responsible for the development of intermediate males. The dominant allele of the recessive repressor, in either its homoorits heteozygous state, activates the Y-chromosomal genes for large or small size, respectively. Accordingly, intermediate males may produce male offspring of all size classes, depending on the presence of either the Y-linked gene or the autosomal repressor.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Electrophoresis 12 (1991), S. 193-203 
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Stretches of short, simple DNA sequences are widespread in all eukaryote genomes studied so far. Simple sequences are thought to undergo frequent expansion and deletion due to intrinsic genomic mechanisms. Some of the simple sequences were used successfully to detect hypervariable loci in various genomes. Hybridization experiments using synthetic probes not only revealed the informative simple repeats suitable for DNA fingerprinting in a particular specie, but also reflected the wide range of distribution of the simple sequences among eukaryotes. The organization of these simple repetitive sequences at the chromosomal loci was investigated using in situ hybridization with chemically synthesized, pure oligonucleotide probes. Both biotin- and digoxigenin-attached probes detected specific chromosomal sites that are enriched in the respective simple-repeat blocks. Depending on the organism and probe used, accumulation of simple DNA sequences at individual or multiple sites on the chromosomes of different vertebrates could be demonstrated. The simple repetitive DNA sequences are located in different chromosomal regions (e. g., heterochromatin on the sex chromosomes, nucleolus organizer regions, and R-band sites), which are constrained considerably during evolution.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Publication Date: 1992-03-01
    Print ISSN: 0009-5915
    Electronic ISSN: 1432-0886
    Topics: Biology , Medicine
    Published by Springer
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  • 7
    Publication Date: 1990-07-01
    Print ISSN: 0340-6717
    Electronic ISSN: 1432-1203
    Topics: Biology , Medicine
    Published by Springer
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