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Genetic and protein polymorphism at CSN1S1 locus in two goat breeds.
No full textGenetic polymorphisms of casein have received a considerable research effort for
many years because of its potential effect on milk composition. Milk composition,
specifically protein content, differs quantitatively and qualitatively among species
and also among breeds and individuals. Sicilian goat breeds seem to be an interesting
model since they have never been under a selection program, and therefore may carry
unique casein polymorphisms. Moreover, the importance of goat milk in infant diets
is growing probably because goat milk in some cases is less allergenic than cow milk.
It is important to evaluate the genetic polymorphisms at the CSN1S1 locus in the
populations of interest, like the Girgentana or Maltese goat breeds, because caseins
are considered as the main cause of allergic reactions. Moreover CSN1S1
polymorphisms have been associated to different levels of this protein
expression in milk. The goal of the present research was twofold 1) to genotype
CSN1S1 locus, and 2) to type casein protein polymorphisms in two Sicilian
breeds, Maltese and Girgentana. Blood and milk samples were obtained from
400 animals (200 of each breed) located in four different flocks. DNA was
extracted from leucocytes and CSN1S1 polymorphisms were detected by PCR
followed by restriction fragment length polymorphism (PCR-RFLP), and by
allele specific PCR (AS-PCR). PCR and digestion products were analyzed by
electrophoresis in 3% agarose gel stained with ethidium bromide after exposure
to ultraviolet light. Milk samples, from the same individuals, were analysed for
protein expression by isoelectrofocusing (IEF). IEF was carried out over a 2.5-
6.0 pH gradient. Protein separation was performed in a polyacrylamide gel, and
stained with Coomassie Brilliant Blue G250. Results showed a high percentage
of A and B alleles (considered strong alleles), but also the presence of weak (F)
and null alleles (N) was found in both breeds. The results may have practical
implications to plan a selection program given that animals with allele A and B
might be useful for cheese production since these animals express more casein
than those carrying F or N alleles, and animals that do not express casein might
be beneficial for hypoallergenic milk production
Casein genes in Cilentana goat breed Proc. of the XLVIII Italian Society of Agricultural Genetics
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Il polimorfismo della caseine caprine: uno straordinario “puzzle” genetico dalle svariate potenzialità applicative
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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
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