Library

X
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
    Electronic Resource
    Electronic Resource
    The paradox of MHC-DRB exon/intron evolution: α-helix and β-sheet encoding regions diverge while hypervariable intronic simple repeats coevolve with β-sheet codons (1993)
    Springer
    Journal of molecular evolution 37 (1993), S. 260-272 
    Details
    ISSN: 1432-1432
    Keywords: MHC class II genes ; Polymorphism ; Gene conversion ; Intron preservation ; Artiodactyls
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Twenty-one different caprine and 13 ovine MHC-DRB exon 2 sequences were determined including part of the adjacent introns containing simple repetitive (gt)n(ga)m elements. The positions for highly polymorphic DRB amino acids vary slightly among ungulates and other mammals. From man and mouse to ungulates the basic (gt)n(ga)m structure is fixed in evolution for 7 × 107 years whereas ample variations exist in the tandem (gt)n and (ga)m dinucleotides and especially their “degenerated” derivatives. Phylogenetic trees for the α-helices and β-pleated sheets of the ungulate DRB sequences suggest different evolutionary histories. In hoofed animals as well as in humans DRB β-sheet encoding sequences and adjacent intronic repeats can be assembled into virtually identical groups suggesting coevolution of noncoding as well as coding DNA. In contrast a-helices and C-terminal parts of the first DRB domain evolve distinctly. In the absence of a defined mechanism causing specific, site-directed mutations, double-recombination or gene-conversion-like events would readily explain this fact. The role of the intronic simple (gt)n(ga)m repeat is discussed with respect to these genetic exchange mechanisms during evolution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00175503
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Simple repetitive sequences are associated with differentiation of the sex chromosomes in the guppy fish (1990)
    Springer
    Journal of molecular evolution 30 (1990), S. 456-462 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF02101117
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Digoxigenated oligonucleotide probes specific for simple repeats in DNA fingerprinting and hybridization in situ (1989)
    Springer
    Human genetics 〈Berlin〉 82 (1989), S. 227-233 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00291160
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Heterogeneities in the distribution of (GACA)n simple repeats in the karyotypes of primates and mouse (1990)
    Springer
    Human genetics 〈Berlin〉 85 (1990), S. 187-194 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00193194
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Specific amplification of the ZFY gene to screen sex in man (1989)
    Springer
    Human genetics 〈Berlin〉 82 (1989), S. 289-290 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using the polymerase chain reaction, a sequence comprising 400 bp of the human ZFY gene was amplified specifically in the male. The method allows detection of the presence of the ZFY gene in the order of 1:104 cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00291174
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Expression of (cac)n/(gtg)n simple repetitive sequences in mRNA of human lymphocytes (1994)
    Springer
    Human genetics 〈Berlin〉 93 (1994), S. 35-41 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Di- and trinucleotide tandem repeat sequences are ubiquitously interspersed and are often polymorphic in the human genome. We have analyzed the transcription of simple (cac) n /(gtg) n repeats in the cDNA of RNA from human lymphocytes. When using such motifs as probes in RNA hybridization experiments, distinct signals are scarcely demonstrable. In order to investigate mRNA sequences that contain such simple repeats, 1 million phage clones from cDNA libraries were screened with the probe (CAC)5. From 50 hybridizing phages, 38 clones were successfully isolated and characterized. The lengths of the transcripts ranged from 120 bp to 3.5 kb. More than 15 different additional simple repeat motifs were found immediately next to or distant to the (cac) n /(gtg) n repeat. In 12 clones, significant homologies were identified with a wide variety of unrelated genes, such as a processed pseudogene of human ubiquitin, serin protease inhibitor genes, a gene candidate from yeast, and sequence-tagged sites of man and mouse. Of the clones, 18% represented mRNA of MHC class I promotor binding protein; 79% displayed novel single copy sequences or partial similarity to many different organelle and nuclear genomes of animal, fungal, bacterial, and viral sequences. These data indicate that short (cac) n /(gtg) n stretches (n ≲ (6) are sometimes contained in open reading frames, but more often in the 3′ and 5′ untranslated portions of mature mRNAs. Longer stretches of perfect simple (cac) n /(gtg) n repeats can rarely be recovered, even from the hnRNA of human lymphocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218910
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Geographic differences in the allele frequencies of the human Y-linked tetranucleotide polymorphism DYS19 (1996)
    Springer
    Human genetics 〈Berlin〉 97 (1996), S. 309-313 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We have studied the allele frequency distribution of the microsatellite locus DYS19 in several populations with different geographical origins worldwide. Three new alleles were found. In addition, remarkable geographic and ethnic differences were observed in the allele frequency profiles and DNA marker (gene) diversity among populations and major ethnic groups. Amerindians showed an overwhelming predominance of the A allele, while in Caucasians the B allele was modal, and in Greater Asians and Africans allele C became predominant. Even within these geographic regions there were significant gradients, as exemplified by the decreasing frequency profile of the B allele from Great Britain over Germany to Slovakia. Thus, DYS19 emerges as a useful tool for studying the structure and dynamics of human populations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02185760
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Geographic differences in the allele frequencies of the human Y-linked tetranucleotide polymorphism DYS19 (1996)
    Springer
    Human genetics 〈Berlin〉 97 (1996), S. 309-313 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We have studied the allele frequency distribution of the microsatellite locus DYS 19 in several populations with different geographical origins worldwide. Three new alleles were found. In addition, remarkable geographic and ethnic differences were observed in the allele frequency profiles and DNA marker (gene) diversity among populations and major ethnic groups. Amerindians showed an overwhelming predominance of the A allele, while in Caucasians the B allele was modal, and in Greater Asians and Africans allele C became predominant. Even within these geographic regions there were significant gradients, as exemplified by the decreasing frequency profile of the B allele from Great Britain over Germany to Slovakia. Thus, DYS 19 emerges as a useful tool for studying the structure and dynamics of human populations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02185760
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    A novel HLA-DR β I sequence from the DRw11 haplotype (1988)
    Springer
    Immunogenetics 28 (1988), S. 208-210 
    Details
    ISSN: 1432-1211
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00375861
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Coding versus intron variability: extremely polymorphic HLA-DRB1 exons are flanked by specific composite microsatellites, even in distant populations (1997)
    Springer
    Human genetics 〈Berlin〉 99 (1997), S. 399-406 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Although microsatellite typing is the dominant method in genome research and indirect gene diagnosis, precise relationships of exonic and adjacent simple repeat polymorphisms are not known. We investigated exon 2 sequences of HLA-DRB1 genes and their neighbouring (GT)n(GA)m repeats including the intervening single copy spacer. DRB1 is the most polymorphic protein-coding locus in man and all vertebrates investigated. The entire DRB1 variability exists in exon 2. DRB1 genes in different haplotype groups (DR1, DR51, DR52, DR8 and DR53) are accompanied by characteristic modifications of the (GT)n(GA)m block (3′ to group-specific single copy spacers). Among more than 520 alleles analysed, 〉 100 different types of microsatellites were observed. The perfect (GT)n and (GA)m blocks vary in length and may be partly ‘degenerated’, mostly in a subgroup-specific manner. Interestingly, the extent of microsatellite diversity varies in given DRB1 alleles. While the microsatellites of the DR7, DR9 alleles and in the DR1 group are virtually invariant, in DR4 and DR13, in particular, simple repeats appear hypervariable with at least 15 or 17 different length alleles, respectively. Comparing Caucasians, Bushmen and South American Indians, the microsatellite variation in identical DRB1 alleles (e.g. DRB1*0102, 03 011, 1302) is smaller than within any of the DR groups in Caucasians. Taken together, extremely polymorphic DRB1 exons evolve in concert with certain variants of an exceptionally well-preserved microsatellite.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004390050379
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...