Search results for " miglioramento"
showing 10 items of 219 documents
Genomic inbreeding estimation in small populations: evaluation of runs of homozygosity in three local dairy cattle breeds
2016
In the local breeds with small population size, one of the most important problems is the increase of inbreeding coefficient (F). High levels of inbreeding lead to reduced genetic diversity and inbreeding depression. The availability of high-density single nucleotide polymorphism (SNP) arrays has facilitated the quantification of F by genomic markers in farm animals. Runs of homozygosity (ROH) are contiguous lengths of homozygous genotypes and represent an estimate of the degree of autozygosity at genome-wide level. The current study aims to quantify the genomic F derived from ROH (F-ROH) in three local dairy cattle breeds. F-ROH values were compared with F estimated from the genomic relati…
Enteric bacteria of food ice and their survival in alcoholic beverages and soft drinks
2017
This study aimed to evaluate the levels of enteric bacteria in ice cubes produced in different environments (home-made, prepared in bars and pubs with ice machines and produced in industrial plants) and to determine their survival in different alcoholic beverages and soft drinks. Members of the Enterobacteriaceae family were found in almost all samples analysed. All industrial and the majority of home-made samples did not contain coliforms. Enterococci were not identified in domestic samples while they were detected in two industrial and three bar/pub samples. The samples collected from bars and pubs were characterized by the highest levels of enteric bacteria. Fourteen strains representing…
Assessment of genetic variation for pathogen-specific mastitis resistance in Valle del Belice dairy sheep
2016
Background: Mastitis resistance is a complex and multifactorial trait, and its expression depends on both genetic and environmental factors, including infection pressure. The objective of this research was to determine the genetic basis of mastitis resistance to specific pathogens using a repeatability threshold probit animal model. Results: The most prevalent isolated pathogens were coagulase-negative staphylococci (CNS); 39 % of records and 77 % of the animals infected at least one time in the whole period of study. There was significant genetic variation only for Streptococci (STR). In addition, there was a positive genetic correlation between STR and all pathogens together (ALL) (0.36 ±…
Genomic characterization of Algerian Guelmoise cattle and their genetic relationship with other North African populations inferred from SNP genotypin…
2018
International audience; Understanding between and within-breeds genetic variability is essential in the choice of conservation management decisions for threatened populations. In this study we assessed the genetic diversity of the Algerian Guelmoise cattle (GUE) by analyzing data on 24 GUE individuals genotyped for the Illumina BovineSNP50 BeadChipv2. We also provided a detailed description of the population structure of GUE using comparisons with 23 worldwide cattle populations, selected as being representative of African, South European and indicine populations, in addition to four North African populations. We show that GUE is an admixed population which has strong genetic similarity to …
Genomic characterization of the Braque Français type Pyrénées dog and relationship with other breeds
2018
The evaluation of genetic variability is a useful research tool for the correct management of selection and conservation strategies in dog breeds. In addition to pedigree genealogies, genomic data allow a deeper knowledge of the variability and genetic structure of populations. To date, many dog breeds, such as small regional breeds, still remain uncharacterized. Braque Français type Pyrénées (BRA) is a dog breed originating from a very old type of gun-dog used for pointing the location of game birds to hunters. Despite the ancient background, the knowledge about levels of genetic diversity, degree of inbreeding and population structure is scarce. This may raise concerns on the possibility …
Whole genome semiconductor based sequencing of farmed European sea bass (Dicentrarchus labrax) Mediterranean genetic stocks using a DNA pooling appro…
2016
European sea bass (Dicentrarchus labrax) is an important marine species for commercial and sport fisheries and aquaculture production. Recently, the European sea bass genome has been sequenced and assembled. This resource can open new opportunities to evaluate and monitor variability and identify variants that could contribute to the adaptation to farming conditions. In this work, two DNA pools constructed from cultivated European sea bass were sequenced using a next generation semiconductor sequencing approach based on Ion Proton sequencer. Using the first draft version of the D. labrax genome as reference, sequenced reads obtained a total of about 1.6 million of single nucleotide polymorp…
Determination of milk production losses and variations of fat and protein percentages according to different levels of somatic cell count in Valle de…
2018
The somatic cell count (SCC) of milk is widely used to monitor udder health and the milk quality and because of its positive genetic correlation with mastitis this trait was included in breeding schemes of dairy sheep. The aim of this study was to estimate the loss in milk yield (MY) and related composition resulting from different levels of somatic cell count in Valle del Belice dairy sheep. Data were collected between 2006 and 2016 in 15 flocks following an A4 recording scheme. Somatic cell count (SCC), fat and protein percentage (F% and P%) were determined using mid-infrared spectroscopy. To evaluate loss in test day MY, F% and P%, five different classes of SCC were arbitrarily defined: …
Penalized classification for optimal statistical selection of markers from high-throughput genotyping: application in sheep breeds
2018
The identification of individuals’ breed of origin has several practical applications in livestock and is useful in different biological contexts such as conservation genetics, breeding and authentication of animal products. In this paper, penalized multinomial regression was applied to identify the minimum number of single nucleotide polymorphisms (SNPs) from high-throughput genotyping data for individual assignment to dairy sheep breeds reared in Sicily. The combined use of penalized multinomial regression and stability selection reduced the number of SNPs required to 48. A final validation step on an independent population was carried out obtaining 100% correctly classified individuals. …
Genome-wide scan of fat-tail sheep identifies signals of selection for fat deposition and adaptation
2018
Fat tail in sheep represents a valuable energy reserve for facing future climate changes. The identification of genes with a role in the fat-tail phenotype may contribute to understanding the physiology of fat deposition and the mechanisms of adaptation. Genotypic data obtained with the OvineSNP50K array in 13 thin-tail sheep breeds from Italy were used to identify selection signatures of fat tail through pairwise thin- versus fat-tail sheep breed comparisons, with the following fat-tail breeds of the Mediterranean area: two unique Italian fat-tail breeds (Barbaresca and Laticauda), a Barbary sheep breed from Libya, Ossimi breed from Egypt, Cyprus Fat-Tail and Chios from the Greek islands …
New insights on water buffalo genomic diversity and post-domestication migration routes from medium density SNP chip data
2018
Made available in DSpace on 2018-12-11T16:52:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-03-02 The domestic water buffalo is native to the Asian continent but through historical migrations and recent importations, nowadays has a worldwide distribution. The two types of water buffalo, i.e., river and swamp, display distinct morphological and behavioral traits, different karyotypes and also have different purposes and geographical distributions. River buffaloes from Pakistan, Iran, Turkey, Egypt, Romania, Bulgaria, Italy, Mozambique, Brazil and Colombia, and swamp buffaloes from China, Thailand, Philippines, Indonesia and Brazil were genotyped with a species-specific medium-dens…