1,721,077 research outputs found
Isolation and characterization of microsatellites in the Adriatic sturgeon (Acipenser naccarii)
No full textWe isolated and characterized seven polymorphic microsatellite loci from a partial genomic library of the Adriatic sturgeon (Acipenser naccarii) enriched for GATA repeats. Variability
was tested in 20 specimens of this endangered species. Our data support the tetraploid condition for A. naccarii and will be useful for the investigation of the remnant genetic variability of this species as well as for genetic tagging studies
Caratterizzazione genetica di popolazioni di Salmo trutta marmoratus (Cuvier, 1817) mediante l'uso di marcatori genetici nucleari: risultati preliminari
No full textThe use of AFLP in sturgeon identification
No full textIn this study a multilocus approach through Amplified
Fragment Length Polymorphism (AFLP) was applied to
species identification of sturgeon commercial products (meat
and caviar) and to identification of interspecific hybrids.
Species identification of commercial products was simply
performed by comparison of electrophoretic profiles with
those of referring species. Concerning interspecific hybrids, the
simultaneous occurrence of the diagnostic bands fixed in the
parental species and a cluster analysis on both fixed and
polymorphic bands allowed a correct identification. The
results strongly suggest that this technique is highly suitable
for analysis of market products as well as precise identification
of species and interspecific hybrids
Duplication polymorphism at MHC class II DRB1 locus in the wild boar (Sus scrofa)
No full textThe origin of allelic polymorphism in genes of the major histocompatibility complex represents a central topic in evolutionary genetics as it is probably the most polymorphic region in the nuclear genome of vertebrates. Accordingly, the analyses of genetic variability at these loci provide evidence complementary to the population genetics studies based on neutral loci. In this study, four wild boar populations, two from Italy (Florence region and Castelporziano Presidential Reserve, outside Rome) and one each from Hungary and Poland, were characterized at a highly polymorphic fragment including part of intron 1 and exon 2 of swine leukocyte antigen (SLA) class II DRB1 gene by direct sequencing and by cloning. Excluding the false alleles, a total of 18 different sequences were observed in 57 individuals. The high ratio of nonsynonymous (dN) vs synonymous (dS) substitution rates in the peptide-binding region supports the hypothesis that balancing selection is operating at this locus. A duplication event at the DRB1 gene was documented only in one Italian population with both copies being putatively active. This is the first evidence of a polymorphism for the number of copies of an SLA gene
Macrostructural Evolution of the Mitogenome of Butterflies (Lepidoptera, Papilionoidea)
No full textThe mitogenome of the species belonging to the Papilionodea (Lepidoptera) is a double stranded circular molecule containing the 37 genes shared by Metazoa. Eight mitochondrial gene orders are known in the Papilionoidea. MIQGO is the plesiomorphic gene order for this superfamily, while other mitochondrial arrangements have a very limited distribution. 2S1GO gene order is an exception and is present in several Lycaenidae and one species of Hesperiidae. We studied the macrostructural changes generating the gene orders of butterflies by analysing a large data set (611 taxa) containing 5 new mitochondrial sequences/assemblies and 87 de novo annotated mitogenomes. Our analysis supports a possible origin of the intergenic spacer trnQ-nad2, characterising MIQGO, from trnM. We showed that the homoplasious gene order IMQGO, shared by butterflies, species of ants, beetles and aphids, evolved through different transformational pathways. We identify a complicated evolutionary scenario for 2S1GO in Lycaenidae, characterised by multiple events of duplication/loss and change in anticodon of trnS1. We show that the gene orders ES1GO and S1NGO originated through a tandem duplication random loss mechanism. We describe two novel gene orders. Ampittia subvittatus (Hesperiidae) exhibits the gene order 2FFGO, characterised by two copies of trnF, one located in the canonical position and a second placed in the opposite strand between trnR and trnN. Bhutanitis thaidina (Papilionidae) exhibits the gene order 4QGO, characterised by the quadruplication of trnQ
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
Exchange between populations of Adamussium colbecki (Mollusca: Bivalvia) in the Ross Sea
No full textThe endemic Antarctic scallop Adamussium colbecki (Mollusca: Bivalvia) represents a key
species in the Ross Sea littoral benthic ecosystem, locally reaching very high densities. This species has an
annual gametogenic cycle, with a summer spawning event, and a pelagic larval behaviour. This paper aims at
describing population structure and genetic polymorphism (using AFLP) of the large populations inhabiting
the Ross Sea (Terra Nova Bay and McMurdo Sound) in order to investigate possible genetic exchange
between A. colbecki in these areas. In Terra Nova Bay, size-frequency distributions show, generally, the
dominance of large individuals, although site related differences are found in the abundance of smaller size
classes (less than 40 mm), suggesting that recruitment is not a regular event. All McMurdo sites are
characterized by large individuals and, at least during this sampling period, recruitment is completely absent.
Nuclear DNA analyses show that the largest differences are found at the largest scale (between McMurdo
Sound and Terra Nova Bay), but all populations sampled, even at a smaller spatial scale, have a well-settled
genetic structure, notwithstanding the pelagic larval strategy. The panmixia hypothesis has therefore to be
rejected for this species
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
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