1,720,971 research outputs found
Complex rearrangement involving 9p deletion and duplication in a syndromic patient : Genotype/phenotype correlation and review of the literature
Full text linkWe describe a 7-year-old boy with a complex rearrangement involving the whole short arm of chromosome 9 defined by means of molecular cytogenetic techniques. The rearrangement is characterized by a 18.3Mb terminal deletion associated with the inverted duplication of the adjacent 21,5Mb region. The patient shows developmental delay, psychomotor retardation, hypotonia. Other typical features of 9p deletion (genital disorders, midface hypoplasia, long philtrum) and of the 9p duplication (brachycephaly, down slanting palpebral fissures and bulbous nasal tip) are present. Interestingly, he does not show trigonocephaly that is the most prominent dysmorphism associated with the deletion of the short arm of chromosome 9. Patient's phenotype and the underlying flanking opposite 9p imbalances are compared with that of reported patients and the proposed critical regions for 9p deletion and 9p duplication syndromes
The structure of duplications on human acrocentric chromosome short arms derived by the analysis of 15p
No full textWe report the molecular analysis of a 130-kb DNA region containing a junction
between beta and non-beta satellite DNA from chromosome 15p. The genomic region
is characterized by beta satellite blocks intermingled with variants of the D4Z4
repeat, and duplicons from 4q24 and 4q35. Besides the p-arm of acrocentric
chromosomes, the duplicons showed a wide genomespread involving pericentromeric,
sub-telomeric, and interstitial regions. In this regard, the paralogous
sequences were characterized by a high similarity index (96%), thus indicating a
recent transposition during the evolution. The acrocentrics differedwith regard
to the location of the 4q24 paralogous region, since it mapped on the p-arm of
chromosomes 13-15 and 21, but only on 22q11.2. Conversely, the 4q35 duplication
marked the p-arm of all the acrocentrics. In different individuals, the short
arm of acrocentric chromosomes revealed a great variability of sequence
representation and location at p11 and/or p13 for both the 4q24 and 4q35
duplications. The studied genomic region from chromosome 15p, of which a contig
of approximately 200 kb has been derived, could lead to more detailed
investigations into the sequence organization and possible biological function
of chromosome regions that are located close to the rDNA arra
Human genome dispersal and evolution of 4q35 duplications and interspersed LSau repeats
No full textWe have investigated the evolutionary history of the 4q35 paralogous region, and
of a sub-family of interspersed LSau repeats. In HSA, 4q35 duplications were
localized at 1q12, 3p12.3, 4q35, 10q26, 20cen, whereas duplicons and
interspersed LSau repeats simultaneously labeled the p arm of acrocentric
chromosomes. A multi-site localization of 4q35-like sequences was also observed
in PTR, GGO, PPY, HLA (Hominoidea) and PAN (Old World monkey), thus indicating
that duplications of this region have occurred extensively in the two clades,
which diverged at least 25 million years ago. In HSA, PTR and PAN, 4q35-derived
duplicons co-localized with rDNA, whereas in GGO and PPY this association was
partially lacking. In PAN, the single- and multi-site distribution of rDNA and
paralogous sequences, respectively, indicates a different timing of sequence
dispersal. The sub-family of interspersed LSau repeats showed a lesser dispersal
than 4q35 duplications both in man and great apes. This finding suggests that
duplications and repeated sequences have undergone different
expansion/contraction events during evolution. The mechanisms underlying the
dispersal of paralogous regions may be further derived through studies comparing
the detailed structural organization of these genomic regions in man and
primates
7p22.1 microduplication syndrome : clinical and molecular characterization of an adult case and review of the literature
No full textA new 7p22.1 microduplication syndrome characterized by intellectual disability, speech delay and craniofacial dysmorphisms, such as macrocephaly, hypertelorism and ear anomalies, has been outlined by the description of two patients with interstitial microduplications confined to 7p22.1 and the recently defined minimal overlapping 430kb critical region including five genes. Here we report on the first adult patient aged 35 years with moderate intellectual disability, psychomotor delay, facial dysmorphisms, cryptorchidism and cardiac anomalies, who carries two close microduplications at 7p22.1 of about 900 and 150kb, respectively. The proximal smaller duplication includes three coding genes and maps outside the minimal described overlapping duplicated region, while the larger one represents the smallest 7p22.1 microduplication reported so far, as it encompasses the entire minimal region with only four additional genes. We compare the phenotype of our patient with that of the few reported cases and discuss on candidate genes in order to enhance the knowledge on genotype-phenotype correlation in 7p22.1 duplication syndrome
Deletion of the AP1S2 gene in a child with psychomotor delay and hypotonia
Full text linkWe identified a 495 Kb interstitial deletion of chromosome Xp22.2, centered on the AP1S2 gene, by means of oligonucleotide array comparative genomic hybridisation (array-CGH) in a child with marked hypotonia in the first months of life, psychomotor retardation, severely delayed walking and speech development, and unspecific dysmorphic facial features. The deletion was inherited from the healthy mother. Point mutations of the AP1S2 gene have been identified in patients with X-linked mental retardation (XLMR). The clinical features of our patient are quite similar to those reported in male patients carrying point mutations, thus suggesting that point mutations and deletions of the AP1S2 gene lead to a recognisable XLMR phenotype in males
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Evolution of Beta Satellite DNA Sequences: Evidence for Duplication-Mediated Repeat Amplification and Spreading
No full textIn this article, we report studies on the evolutionary history of beta satellite
repeats (BSR) in primates. In the orangutan genome, the bulk of BSR sequences
was found organized as very short stretches of approximately 100 to 170 bp,
embedded in a 60-kb to 80-kb duplicated DNA segment. The estimated copy number
of the duplicon that carries BSR sequences ranges from 70 to 100 per orangutan
haploid genome. In both macaque and gibbon, the duplicon mapped to a single
chromosomal region at the boundary of the rDNA on the marker chromosome
(chromosome 13 and 12, respectively). However, only in the gibbon, the duplicon
comprised 100 bp of beta satellite. Thus, the ancestral copy of the duplicon
appeared in Old World monkeys ( approximately 25 to approximately 35 MYA),
whereas the prototype of beta satellite repeats took place in a gibbon ancestor,
after apes/Old World monkeys divergence ( approximately 25 MYA). Subsequently, a
burst in spreading of the duplicon that carries the beta satellite was observed
in the orangutan, after lesser apes divergence from the great apes-humans
lineage ( approximately 18 MYA). The analysis of the orangutan genome also
indicated the existence of two variants of the duplication that differ for the
length (100 or 170 bp) of beta satellite repeats. The latter organization was
probably generated by nonhomologous recombination between two 100-bp repeated
regions, and it likely led to the duplication of the single Sau3A site present
in the 100-bp variant, which generated the prototype of Sau3A 68-bp beta
satellite tandem organization. The two variants of the duplication, although
with a different ratios, characterize the hominoid genomes from the orangutan to
humans, preferentially involving acrocentric chromosomes. At variance to alpha
satellite, which appeared before the divergence of New World and Old World
monkeys, the beta satellite evolutionary history began in apes ancestor, where
we have first documented a low-copy, nonduplicated BSR sequence. The first step
of BSR amplification and spreading occurred, most likely, because the BSR was
part of a large duplicon, which underwent a burst dispersal in great apes'
ancestor after the lesser apes' branching. Then, after orangutan divergence, BSR
acquired the clustered structural organization typical of satellite DNA
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