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Il polimorfismo delle caseine caprine: uno straordinario “puzzle” genetico dalle svariate potenzialità applicative
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Casein genes in Cilentana goat breed
No full textIt is well known that casein genes are organized as a cluster including alphas1-casein (CSN1S1), betacasein
(CSN2), l'alphas2-casein (CSN1S2) and k-casein (CSN3). In the last years, the genetic
polymorphism of goat casein has raised a considerable research interest due to its direct relationships
with milk quality, composition and technological characteristics. Researches mainly concern CSN1S1
fraction, characterised by a high polymorphism, both at qualitative and quantitative level, strongly
affecting the technological and nutritional properties of goat milk. CSN1S1 locus is controlled by
several autosomic alleles, as already shown by the studies carried out at protein level by milk
electrophoretic analysis. Recently, it has been possible to identify a great number of mutations
affecting transcription and/or translation of casein genes by means of analysis techniques of genomic
DNA and messenger RNA. In particular, mutations responsible for the reduced level of expression of
some of the CSN1S1 and CSN1S2 alleles, and for the absence of the protein fractions synthesised by
each of the calcium-sensitive casein genes CSN1S1, CSN1S2, and CSN2 have been identified in goat.
Moreover, recent studies on goat CSN3 confirmed the occurrence of protein genetic polymorphism,
and identified several mutations responsible of different protein phenotypes at DNA level, as well as
a number of synonymous nucleotide exchanges. Currently, more than 14 alleles were identified at
goat CSN3 locus.
Due to the tight association occurring among casein genes, the estimation of the relationships
between casein variants and milk traits can be improved by considering the entire casein haplotype
instead of individual genotypes,. In fact, the effect of an allele at a given locus could be confounded
with the effect of linked alleles at another locus. Moreover, selection for an allele could
automatically increase the frequency of linked alleles which could not present a favourable effect on
the trait of interest. In conclusion, the study at haplotype level is necessary to detect important effects
which could be used for genetic improvement of goat breeds aiming to preserve bio-diversity, to
safeguard typical products, and to the valorise the particular nutritional and hypo-allergenic
properties of some casein haplotypes.
The aim of this work was to study the casein gene and haplotype variability in the Cilentana goat
breed. A total of 50 individual milk samples were analysed by isoelectrofocusing. Moreover, DNA
was extracted from milk and analysed by different molecular techniques to assess the occurrence of
different polymorphisms not detectable at the protein level.
Particular attention was given to the presence of null alleles, which are important for the eventual
breeding of goat lines specifically devoted to the production of hypo-allergenic milk. Some
heterozygous goats for CSN2*0 allele were identified. The possibility of selecting casein haplotypes
carrying CSN2*0 allele is discussed, as well as of crossing northern goat breeds, characterised by the
occurrence of CSN1S1*0 allele, with southern caprine populations, which contain null alleles mainly
at CSN2 and CSN1S2 in their genome. At CSN3 locus, the predominant allele was CSN3*D
(GenBank acc. number AY166705) differing from CSN3*A only for the Val (CSN3*A) to Ile
exchange at position 119 of the mature protein. Null alleles do not occur at this locus, which could as
well be of interest for nutritional purposes due to biological properties of its peptide components
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
Effects of casein haplotype on milk production traits in Italian Holstein and Brown Swiss cattle
No full textThe objective of this study was to estimate the effects of different haplotypes of the casein genes on milk production traits in Italian dairy cattle. Traits of interest were yields of milk, fat, and protein, and percentages of fat and protein in milk. The data included 728 multiparous records from 347 Holsteins and 773 records from 298 Brown Swiss cows. Records were preadjusted for effects of age and parity, season of calving, and region, and expressed as deviations from herdmate averages. Twenty half-sib families were represented in each breed. Haplotype probabilities were estimated for each animal and phenotypes were regressed on these probabilities. Nine haplotypes were observed in Holsteins and 17 were identified among the Brown Swiss. For Holsteins, significant effects were observed for protein percentage, with some indication of an effect for fat percentage. For the Brown Swiss, effects of haplotypes were significant for milk yield and fat and protein percentages. Effects were strongest for protein percentage. Correlation coefficients of solutions across breeds tended to be strong and positive, indicating that the same haplotypes had similar estimated effects in the 2 breeds. Although the data were limited (<350 cows in each study), this latter result may suggest that genes in the casein complex itself are responsible for the effects observed, rather than loci that are physically linked on either side of the casein cluster
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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