Search results for " Genomica"

Caratterizzazione genomica delle razze bovine autoctone italiane

2018

Negli ultimi cinquant'anni, a causa della sostituzione con le razze cosmopolite, le razze zootecniche locali hanno subito una forte contrazione numerica. Tuttavia, esse rappresentano un’importante patrimonio, in grado, tra le altre cose, di valorizzare ambienti marginali. Sono spesso legate anche a produzioni tipiche di alta qualità. La loro caratterizzazione rappresenta un passo essenziale verso eventuali piani di recupero, conservazione e valorizzazione. Il presente studio è stato condotto al fine di caratterizzare a livello genomico le razze bovine locali allevate in Italia. Sono stati campionati un totale di 814 animali appartenenti a 30 razze italiane e a 2 razze cosmopolite (Charolais…

Genetica

2006

Algoritmica Per Le Scienze Della Vita

2011

Capito dove si esemplifica come l' algoritmica contribuisce a carpire i segreti della Monna Lisa della scienza moderna.

Genetic selection for reduced Somatic Cell Counts in sheep milk: A review

2015

Mastitis is an inflammation of the udder, mainly caused by bacteria, and leads to economic loss, due to discarded milk, reduced milk production, reduced milk quality and increased health costs in both dairy sheep and cattle. Selecting for increased genetic resistance to mastitis can be done directly or indirectly, with the indirect selection corresponding to a prediction of the bacteriological status of the udder based on traits related to the infection. The most frequently used indirect method is currently milk somatic cell count (SCC) or somatic cell score (SCS). This review reports the state of the art relating to the genetic basis of mastitis resistance in sheep and explores the opportu…

Genetic parameters for somatic cell score according to udder infection status in Valle del Belice dairy sheep and impact of imperfect diagnosis of in…

2010

Abstract Background Somatic cell score (SCS) has been promoted as a selection criterion to improve mastitis resistance. However, SCS from healthy and infected animals may be considered as separate traits. Moreover, imperfect sensitivity and specificity could influence animals' classification and impact on estimated variance components. This study was aimed at: (1) estimating the heritability of bacteria negative SCS, bacteria positive SCS, and infection status, (2) estimating phenotypic and genetic correlations between bacteria negative and bacteria positive SCS, and the genetic correlation between bacteria negative SCS and infection status, and (3) evaluating the impact of imperfect diagno…

Relationship between beta lactoglobulin and subclinical mastitis in Valle del Belice sheep breed

2010

The objective of the following research was to determine the effect of LGB genotypes on subclinical mastitis in Valle del Belice dairy sheep. Ewes were classified as affected or not by subclinical mastitis within a lactation based on i) a positive culture in one of the test-days and ii) more than 750,000 somatic cells. Generalized linear mixed models were fitted to assess the significance of LGB genotypes on MTB and MTC. The LGB genotypes significantly affected MTB (p=0.0387), and showed a tendency on MTC (p=0.1104). Least square means showed that in the analysis for MTB, individuals with genotypes BB and AB had a higher frequency of subclinical mastitis. Moreover, the least square differen…

Effect of somatic cell count level on functional longevity in Valle del Belice dairy sheep assessed using survival analysis.

2009

The objectives of this study were to evaluate the effect of somatic cell count (SCC) on functional longevity and to estimate the heritability of functional longevity using survival analysis in Valle del Belice dairy sheep. A total of 4,880 lactations of 2,190 ewes from 11 flocks were used. In this study, SCC was considered as an indication of subclinical mastitis. In case of clinical cases, identified by the technicians at milking time, test-day weights and milk samples of those ewes were not considered. Somatic cells were analyzed as counts, without any transformation, and were grouped in 3 classes based on the observed SCC maximum (mxSCC). The mxSCC classes, expressed as 103 cells/mL, wer…

Time-to-event analysis of mastitis at first-lactation in Valle del Belice ewes

2007

A time-to-event study for mastitis at first-lactation in Valle del Belice ewes was conducted, using survival analysis with an animal model. The goals were to evaluate the effect of lambing season and level of milk production on the time from lambing to the day when a ewe experienced a test-day with a recorded SCC greater than or equal to 750,000 cells/ml, and to estimate, for this trait, its heritability and the percentage of variation explained by the flock-year of lambing effect. A dataset with 2468 first-lactation records, collected from 1998 to 2003 in Valle del Belice ewes allocated in 17 flocks, was used. The Cox model used included lambing season and total milk yield adjusted for lac…

A deterministic simulation study of embryo marker-assisted selection for age at first calving in Nellore (Bos indicus) beef cattle

2007

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T19:04:58Z No. of bitstreams: 1 S1415-47572007000400008.pdf: 85300 bytes, checksum: 7422029b120457123fb366c1bd71e758 (MD5) Made available in DSpace on 2013-08-22T19:04:58Z (GMT). No. of bitstreams: 1 S1415-47572007000400008.pdf: 85300 bytes, checksum: 7422029b120457123fb366c1bd71e758 (MD5) Previous issue date: 2007-01-01 Made available in DSpace on 2013-09-30T20:08:32Z (GMT). No. of bitstreams: 2 S1415-47572007000400008.pdf: 85300 bytes, checksum: 7422029b120457123fb366c1bd71e758 (MD5) S1415-47572007000400008.pdf.txt: 39461 bytes, checksum: 2796161439379a834535eeaff8aac2ba (MD5) Previous issue date: 2007-01-01 Submitt…

Data from: Low but contrasting neutral genetic differentiation shaped by winter temperature in European great tits

2015

Gene flow is usually thought to reduce genetic divergence and impede local adaptation by homogenising gene pools between populations. However, evidence for local adaptation and phenotypic differentiation in highly mobile species, experiencing high levels of gene flow, is emerging. Assessing population genetic structure at different spatial scales is thus a crucial step towards understanding mechanisms underlying intraspecific differentiation and diversification. Here, we studied the population genetic structure of a highly mobile species – the great tit Parus major – at different spatial scales. We analysed 884 individuals from 30 sites across Europe including 10 close-by sites (< 50 km)…