Search results for "sheep breed"
showing 10 items of 29 documents
Association study between beta-defensin gene polymorphisms and mastitis resistance in Valle del Belice dairy sheep breed
2016
Abstract Mastitis is generally caused by bacteria, and it is the most common disease in livestock species. Defensins are peptides with a broad spectrum of antimicrobial activity and β-defensin genes have been studied in several livestock species due to their important role in the innate immune response. The aim of this study was to establish an association between polymorphisms in the β-defensin 1 and 2 genes and mastitis resistance in the Valle del Belice dairy sheep. Data consisted of 1855 and 2804 observations for case and control group, respectively. Six single nucleotide polymorphisms and seven haplotypes were selected for association studies with mastitis. In particular, polymorphism …
Runs of homozygosity reveal genome-wide autozygosity in Italian sheep breeds
2018
The availability of dense single nucleotide polymorphism (SNP) assays allows for the determination of autozygous segments based on runs of consecutive homozygous genotypes (ROH). The aim of the present study was to investigate the occurrence and distribution of ROH in 21 Italian sheep breeds using medium-density SNP genotypes in order to characterize autozygosity and identify genomic regions that frequently appeared in ROH within individuals, namely ROH islands. After filtering, the final number of animals and SNPs retained for analyses were 502 and 46 277 respectively. A total of 12 302 ROH were identified. The mean number of ROH per breed ranged from 10.58 (Comisana) to 44.54 (Valle del B…
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. …
A melanocortin 1 receptor (MC1R) gene polymorphism is useful for authentication of Massese sheep dairy products
2011
Massese is an Italian sheep breed, with black or grey coat colour, mainly reared in the Tuscany and Emilia Romagna regions. Recently, the emerging interests in this breed have resulted in the production of Pecorino cheese obtained with only Massese milk. In order to be profitable, this marketing link between Massese breed and its products should be defended against fraudsters who could include milk of other sheep breeds or cow milk in Massese labelled productions. To identify the genetic factors affecting coat colour in sheep, we have recently analysed the melanocortin 1 receptor (MC1R) gene and identified several single nucleotide polymorphisms (SNPs). In this work, as a first step to set …
Comparison of selection criteria for milk yield traits of Valle del Belice dairy sheep.
2006
Abstract The objectives of this work were to investigate alternative selection criteria for milk yield traits in the Valle del Belice sheep breed, which are either corrected for lactation length or not affected by lactation length, to estimate genetic parameters for these alternative selection criteria and to compare the estimated breeding values. The genetic correlations show that corrected milk yield (CMY), maximum test-day yield (MTY) and milk yield at hundred days (MYH), are moderately or weakly correlated with lactation length (LL) ( r g = 0.58, 0.16 and 0.39, respectively). Higher genetic correlation was found between total milk yield (TMY) and LL ( r g = 0.73). Rank correlations be…
Combined approaches to identify genomic regions involved in phenotypic differentiation between low divergent breeds: Application in Sardinian sheep p…
2019
Selective breeding has led to modifications in the genome of many livestock breeds. In this study, we identified the genomic regions that may explain some of the phenotypic differences between two closely related breeds from Sardinia. A total of 44 animals, 20 Sardinian Ancestral Black (SAB) and 24 Sardinian White (SW), were genotyped using the Illumina Ovine 50K array. A total of 68, 38 and 15 significant markers were identified using the case–control genome-wide association study (GWAS), the Bayesian population differentiation analysis (FST) and the Rsb metric, respectively. Comparisons among the approaches revealed a total of 22 overlapping markers between GWAS and FST and one marker bet…
High-Density Genomic Characterization of Native Croatian Sheep Breeds
2022
A recent comprehensive genomic analysis based on 50K SNP profiles has shown that the regional Balkan sheep populations have considerable genetic overlap but are distinctly different from surrounding breeds. All eight Croatian sheep breeds were represented by a small number of individuals per breed. Here, we genotyped 220 individuals representing the native Croatian sheep breeds (Istrian Sheep, Krk Island Sheep, Cres Island Sheep, Rab Island Sheep, Lika Pramenka, Pag Island Sheep, Dalmatian Pramenka, Dubrovnik Sheep) and mouflon using the Ovine Infinium® HD SNP BeadChip (606,006 SNPs). In addition, we included publicly available Balkan Pramenka and other Mediterranean sheep breeds. Our analy…
High-density genomic characterization of native Croatian sheep breeds
2022
A recent comprehensive genomic analysis based on 50K SNP profiles has shown that the regional Balkan sheep populations have considerable genetic overlap but are distinctly different from surrounding breeds. All eight Croatian sheep breeds were represented by a small number of individuals per breed. Here, we genotyped 220 individuals representing the native Croatian sheep breeds (Istrian Sheep, Krk Island Sheep, Cres Island Sheep, Rab Island Sheep, Lika Pramenka, Pag Island Sheep, Dalmatian Pramenka, Dubrovnik Sheep) and mouflon using the Ovine Infinium® HD SNP BeadChip (606, 006 SNPs). In addition, we included publicly available Balkan Pramenka and other Mediterranean sheep breeds. Our anal…
Identification of Copy Number Variations and Genetic Diversity in Italian Insular Sheep Breeds
2022
Simple Summary The aim of this work is to identify CNVs and perform a CNV-based population genetics analysis in five Italian sheep breeds (Barbaresca, Comisana, Pinzirita, Sarda, and Valle del Belìce). We identified 10,207 CNVs and 365 CNV regions (CNVRs). The different approaches used to disclose the genetic relationship showed that the five breeds tend to cluster in distinct groups. Gene enrichment was described for the 37 CNVRs selected considering the top 10%. Gene Ontology analysis showed that several of these genes are involved in lipid metabolism, immune response, and the olfactory pathway. CNVs represent valuable molecular resources to provide useful information for separating the p…
Parentage verification of Valle del Belice dairy sheep using multiplex microsatellite panel
2013
Abstract The aim of this work was to develop and evaluate a PCR based microsatellite markers multiplex system for parentage verification of Sicilian Valle del Belice dairy sheep. A total of 85 samples of blood and hair were collected and genotyped for 24 microsatellite markers in multiplex electrophoresis runs. A total of 269 alleles were detected across the 24 loci investigated. The PIC considering all loci was equal to 0.736, showing that this microsatellite panel was very polymorphic and highly informative. A parentage test was performed on 64 families generated with multiple sires. Results indicated 20.3% and 29.7% misidentification rates for females and males, respectively. In 8 cases,…