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  • 1
    Digitale Medien
    Digitale Medien
    Exonic MHC-DRB Polymorphisms and Intronic Simple Repeat Sequenees: Janus’Faces of DNA Sequence Evolution (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Immunological reviews 143 (1995), S. 0 
    Details
    ISSN: 1600-065X
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: The evolution of highly polymorphic gene loci is following routes that cannot be extrapolated from the existing knowledge of single copy genes. In addition, interpreting the evolution of the most polymorphic loci in vertebrates requires a plethora of data from different taxa. We evaluate here the rules for the evolution of Major Histocompatibility Complex (MHC-)DRB genes recently established in humans and other primates on the basis of sequences from several artiodactyl species. MHC genes encode essential molecules for self/altered-self/non-self discrimination in the interaction of the organism with its environment. The necessity to effectively present various different antigens to immunocompetent cells causes positive selection pressure on the variability of these genes in the population. Artiodactyls represent the third mammalian order in which this phenomenon was evidenced independently. A further incentive to investigate also the surroundings of MHC-DRB loci was the presence of a particular repetitive sequence stretch in the vicinity of the polymorphic exon - in addition to the evolutionarily old alleles, ancient polymorphisms and the mechanisms for their generation and/or maintenance. Besides their utility for indirect gene diagnosis (MHC-DRB typing), the closely linked stretches of simple repetitive DNA in the neighborhood of the highly polymorphic MHC-DRB genes are also interesting remains of the evolutionary history. Evolutionary developmenl is different in genetically inert intron-ic DNA compared to the exonic counterparts, despite their close vicinity. The persistence of these simple repeats over nearly 100 million years in one location preserving the same basic motif structure is startling. Indirect evidence is weighed that biological meaning should be considered for these elements. The combined analysis of the polymorphic DRB genes and the (highly variable but persistent) simple repeat stretches deepen our understanding of the complexities within a unique genomic compartment encoding essential molecules for self/non-self dif-ferentiation in the interaction of the organism with its environment.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1600-065X.1995.tb00676.x
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  • 2
    Digitale Medien
    Digitale Medien
    Expansion of a novel CAG trinucleotide repeat in the 5′ region of PPP2R2B is associated with SCA12 (1999)
    [s.l.] : Nature America Inc.
    Nature genetics 23 (1999), S. 391-392 
    Details
    ISSN: 1546-1718
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Medizin
    Notizen: [Auszug] The genetic aetiologies of at least 20% of autosomal dominant spinocerebellar ataxias (SCAs) have yet to be elucidated. We have recently identified a novel form of autosomal dominant SCA, termed SCA12, in a large pedigree ('R') of German descent. The phenotype is variable, but the ...
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1038/70493
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  • 3
    Digitale Medien
    Digitale Medien
    Mutations in ENPP1 are associated with 'idiopathic' infantile arterial calcification (2003)
    [s.l.] : Nature Publishing Group
    Nature genetics 34 (2003), S. 379-381 
    Details
    ISSN: 1546-1718
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Medizin
    Notizen: [Auszug] Idiopathic infantile arterial calcification (IIAC; OMIM 208000) is characterized by calcification of the internal elastic lamina of muscular arteries and stenosis due to myointimal proliferation. We analyzed affected individuals from 11 unrelated kindreds and found that IIAC was associated with ...
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1038/ng1221
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  • 4
    Digitale Medien
    Digitale Medien
    A bisexually reproducing all-triploid vertebrate (2002)
    [s.l.] : Nature Publishing Group
    Nature genetics 30 (2002), S. 325-328 
    Details
    ISSN: 1546-1718
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Medizin
    Notizen: [Auszug] Green toads are common in the Palaearctic region, where they have differentiated into several taxa. The toads exist with variable amounts of ploidy, similar to other anuran species or reptiles. In vertebrate biology, the very rare occurrence of triploidy is coupled with infertility or unisexuality, ...
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1038/ng839
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  • 5
    Digitale Medien
    Digitale Medien
    AlaSOPro mutation in the gene encoding α-synuclein in Parkinson's disease (1998)
    [s.l.] : Nature Publishing Group
    Nature genetics 18 (1998), S. 106-108 
    Details
    ISSN: 1546-1718
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Medizin
    Notizen: [Auszug] Parkinson's disease (PD) is characterized by progressive neuronal degeneration which predominantly affects the dopaminergic neurons in the nigrostriatal system but also several other regions of the brain1. A specific pathological feature of the disease is the presence of intracytoplas-mic inclusion ...
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1038/ng0298-106
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  • 6
    Digitale Medien
    Digitale Medien
    Elternschaftsnachweise bei TrauerschnäppernFicedula hypoleuca am Westrand ihres mitteleuropäischen Verbreitungsareals (1996)
    Springer
    Journal of ornithology 137 (1996), S. 435-446 
    Details
    ISSN: 1439-0361
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Bei Lingen/Emsland (52.27° N, 7.15° E) in Norddeutschland wurden 31 Trauerschnäpperbruten mit Hilfe des Oligonukleotid DNA-Fingerprintings untersucht. In 4 Bruten (12,9 %) fanden sich insgesamt 9 Nestlinge, die auf Fremdkopulationen der ♀ zurückgingen. Ihr Anteil an der Gesamtzahl der Nestlinge (n=165) betrug 5,5 %. Bezieht man den Verpaarungsstatus der ♂ in die Betrachtungen ein, findet sich ein signifikanter Unterschied: Nur eines von 20 anscheinend monogam verpaarten ♂ wurde „betrogen“, dagegen fanden sich bei nicht weniger als 3 von 7 bigyn verpaarten ♂ Nestlinge, die auf Fremdkopulationen der ♀ zurückgingen. Der Anteil betrogener bigyner ♂ wird dabei unter Umständen sogar unterschätzt, da in drei Fällen die Primärbruten nicht untersucht werden konnten.
    Notizen: Abstract The study deals with the occurrence of extra-pair copulations within a Pied Flycatcher population near Lingen/Emsland (52.27° N, 7.15 ° E) in northern Germany. As a whole, 31 Pied Flycatcher broods were investigated using oligonucleotide DNA finger-printing. In 4 broods (12.9 %) a sum of 9 nestlings were found to be due to extra-pair copulations of the females. Their proportion with regard to the total number of nestlings investigated (n=165) amounts to 5.5 %. Integrating the pairing status of males into the analyses a significant difference was found: Only one of 20 obviously monogamous males was cuckolded, while for 3 of 7 bigyneous males' nestlings were identified that resulted from extra-pair copulations of the females. The proportion of cuckolded bigyneous males may be even underestimated, because in three cases the primary broods could not be investigated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01661100
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  • 7
    Digitale Medien
    Digitale Medien
    SCA2 trinucleotide expansion in German SCA patients (1997)
    Springer
    Neurogenetics 1 (1997), S. 59-64 
    Details
    ISSN: 1364-6753
    Schlagwort(e): Keywords: spinocerebellar ataxia, SCA2, trinucleotide repeat expansion, octogenarians, repeat instability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: ABSTRACT Autosomal dominant spinocerebellar ataxias (SCA) are a group of clinically and genetically heterogeneous neurodegenerative disorders which lead to progressive cerebellar ataxia. A gene responsible for SCA type 2 has been mapped to human chromosome 12 and the disease causing mutation has been identified as an unstable and expanded (CAG)n trinucleotide repeat. We investigated the (CAG)n repeat length of the SCA2 gene in 842 patients with sporadic ataxia and in 96 German families with dominantly inherited SCA which do not harbor the SCA1 or MJD1/SCA3 mutation, respectively. The SCA2 (CAG)n expansion was identified in 71 patients from 54 families. The (CAG)n stretch of the affected allele varied between 36 and 64 trinucleotide units. Significant repeat expansions occurred most commonly during paternal transmission. Analysis of the (CAG)n repeat lengths with the age of onset in 41 patients revealed an inverse correlation. Two hundred and forty-one apparently healthy octogenerians carried alleles between 16 and 31 repeats. One 50-year old, healthy individual had 34 repeats; she had transmitted an expanded allele to her child. The small difference between ‘normal’ and disease alleles makes it necessary to define the extreme values of their ranges. With one exception, the trinucleotide expansion was not observed in 842 ataxia patients without a family history of the disease. The SCA2 mutation causes the disease in nearly 14% of autosomal dominant SCA in Germany.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s100480050009
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  • 8
    Digitale Medien
    Digitale Medien
    DNA fingerprinting of Ascochyta rabiei with synthetic oligodeoxynucleotides (1991)
    Springer
    Current genetics 19 (1991), S. 483-489 
    Details
    ISSN: 1432-0983
    Schlagwort(e): DNA fingerprinting ; Synthetic oligodeoxynucleotides ; Simple repetitive sequences ; Fungal pathotypes ; Ascochyta rabiei
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The ascomycete fungus Ascochyta rabiei, an important pathogen of the grain legume crop chickpea (Cicer arietinum L.) in the Mediterranean region, has not been adequately characterized in molecular terms. We therefore used DNA fingerprinting, with synthetic oligodeoxynucleotides complementary to simple repetitive sequences, to pathotype different isolates of the fungus. Six single-spored A. rabiei isolates were first categorized using a host differential set of nine chickpea genotypes. Seedlings were inoculated under controlled environmental conditions, and disease severity was recorded 9 days after inoculation. DNA was extracted from in vitro-grown mycelia of the six purified fungal isolates, restricted with EcoRI, HinfI, MboII and TaqI, and fingerprinted with radiolabeled (GATA)4, (GTG)5, (CA)8, and (TCC)5, respectively. High levels of polymorphism were detected with optimal enzyme/probe combinations that allow one to discriminate between the isolates. The potential of DNA fingerprinting with simple repetitive sequences can thus be expanded to the identification of fungal races and pathotypes. The characterization of the geographic distribution and genetic variability of pathotypes will facilitate the selection of suitable host cultivars to be grown in specific regions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00312740
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  • 9
    Digitale Medien
    Digitale Medien
    Differentiation of species and strains among filamentous fungi by DNA fingerprinting (1991)
    Springer
    Current genetics 19 (1991), S. 239-242 
    Details
    ISSN: 1432-0983
    Schlagwort(e): DNA fingerprinting of filamentous fungi ; Penicillium ; Trichoderma ; Aspergillus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We have analyzed 11 strains and clones, representing five species (Penicillium janthinellum, P. citrioviridae, P. chrysogenum, Aspergillus niger, Trichoderma harzianum) and three genera of filamentous fungi, for the presence of hypervariable loci in their genomes by hybridization with simple repeat oligonucleotides and the DNA of phage M13. The oligonucleotide probes (CT)8, (GTG)5 and (GACA)4, as well as M13 DNA, are informative probes for fingerprinting in all genera and species tested. The probe (GATA)4 produced informative fingerprints only with the genomic DNA of A. niger. There was no similarity between the fingerprints originating from fungi of different genera and also little similarity between the fingerprints of different species belonging to the same genus. Fingerprints of strains of the same species differed only slightly from each other. Fingerprints of clones originating from one strain were identical. The results indicate that DNA fingerprinting is a powerful method to differentiate species and strains of filamentous fungi.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00336493
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  • 10
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): MHC class II genes ; Polymorphism ; Gene conversion ; Intron preservation ; Artiodactyls
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00175503
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