Assessment of inbreeding resulting from selection for scrapie resistance: a model for rare sheep breeds

Brown, Cameron; Orford, Michael; Tzamaloukas, Ouranios; Mavrogenis, A. P.; Miltiadou, Despoina

doi:10.1136/vr.102503

Cited by 4 publications

(4 citation statements)

References 38 publications

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“…While research and application of genomic tools in livestock is occurring in many commercial/transboundary breeds (e.g., Pryce et al, 2014 ; Scraggs et al, 2014 ), its application in less commercial populations is sporadic and the scientific basis of decisions on management of indigenous livestock, for example in which germplasm to store, assessing the effects of upgrading or evaluating ongoing genetic management is therefore highly variable (e.g., Brown et al, 2014 ; FAO, 2015b ). This points to the reality that genetically-based prioritization is unlikely to be operational in the absence of other considerations, including commercial reality and the ecosystem/production environment (e.g., Sanderson et al, 2013 ).…”

Section: Methods and Resultsmentioning

confidence: 99%

Prospects and challenges for the conservation of farm animal genomic resources, 2015-2025

et al. 2015

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Livestock conservation practice is changing rapidly in light of policy developments, climate change and diversifying market demands. The last decade has seen a step change in technology and analytical approaches available to define, manage and conserve Farm Animal Genomic Resources (FAnGR). However, these rapid changes pose challenges for FAnGR conservation in terms of technological continuity, analytical capacity and integrative methodologies needed to fully exploit new, multidimensional data. The final conference of the ESF Genomic Resources program aimed to address these interdisciplinary problems in an attempt to contribute to the agenda for research and policy development directions during the coming decade. By 2020, according to the Convention on Biodiversity's Aichi Target 13, signatories should ensure that “…the genetic diversity of …farmed and domesticated animals and of wild relatives …is maintained, and strategies have been developed and implemented for minimizing genetic erosion and safeguarding their genetic diversity.” However, the real extent of genetic erosion is very difficult to measure using current data. Therefore, this challenging target demands better coverage, understanding and utilization of genomic and environmental data, the development of optimized ways to integrate these data with social and other sciences and policy analysis to enable more flexible, evidence-based models to underpin FAnGR conservation. At the conference, we attempted to identify the most important problems for effective livestock genomic resource conservation during the next decade. Twenty priority questions were identified that could be broadly categorized into challenges related to methodology, analytical approaches, data management and conservation. It should be acknowledged here that while the focus of our meeting was predominantly around genetics, genomics and animal science, many of the practical challenges facing conservation of genomic resources are societal in origin and are predicated on the value (e.g., socio-economic and cultural) of these resources to farmers, rural communities and society as a whole. The overall conclusion is that despite the fact that the livestock sector has been relatively well-organized in the application of genetic methodologies to date, there is still a large gap between the current state-of-the-art in the use of tools to characterize genomic resources and its application to many non-commercial and local breeds, hampering the consistent utilization of genetic and genomic data as indicators of genetic erosion and diversity. The livestock genomic sector therefore needs to make a concerted effort in the coming decade to enable to the democratization of the powerful tools that are now at its disposal, and to ensure that they are applied in the context of breed conservation as well as development.

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Section: Methods and Resultsmentioning

confidence: 99%

Prospects and challenges for the conservation of farm animal genomic resources, 2015-2025

et al. 2015

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“…Management of deleterious mutations may be integrated within selection and conservation schemes (see Box ). For instance, the European Union implemented a genotyping and breeding programme to decrease and monitor scrapie susceptibility in sheep (including local and rare sheep breeds), which is associated with polymorphism in the prion protein gene (PRP, Brown, Orford, Tzamaloukas, Mavrogenis, & Miltiadou, ).…”

Section: Components Of Genetic Erosionmentioning

confidence: 99%

Next‐generation metrics for monitoring genetic erosion within populations of conservation concern

Leroy

Carroll

Bruford

et al. 2017

Evolutionary Applications

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Genetic erosion is a major threat to biodiversity because it can reduce fitness and ultimately contribute to the extinction of populations. Here, we explore the use of quantitative metrics to detect and monitor genetic erosion. Monitoring systems should not only characterize the mechanisms and drivers of genetic erosion (inbreeding, genetic drift, demographic instability, population fragmentation, introgressive hybridization, selection) but also its consequences (inbreeding and outbreeding depression, emergence of large‐effect detrimental alleles, maladaptation and loss of adaptability). Technological advances in genomics now allow the production of data the can be measured by new metrics with improved precision, increased efficiency and the potential to discriminate between neutral diversity (shaped mainly by population size and gene flow) and functional/adaptive diversity (shaped mainly by selection), allowing the assessment of management‐relevant genetic markers. The requirements of such studies in terms of sample size and marker density largely depend on the kind of population monitored, the questions to be answered and the metrics employed. We discuss prospects for the integration of this new information and metrics into conservation monitoring programmes.

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“…The importance of maintaining a diverse livestock population has previously been emphasised, enabling optimal utilisation of the pastoral system, maintaining access to a broad gene pool for further breed advancement in productivity or health characteristics, for advancement of human and animal health, and ensuring variation in the advent of novel disease emergence. [1][2][3][4] .…”

Section: Introductionmentioning

confidence: 99%

“…Rare breeds of British livestock are of inherent importance to the diversity of the UK livestock industry, with applications in conservation grazing, stewardship schemes and maintaining the genetic diversity of the livestock population. The importance of maintaining a diverse livestock population has previously been emphasised, enabling optimal utilisation of the pastoral system, maintaining access to a broad gene pool for further breed advancement in productivity or health characteristics, for advancement of human and animal health, and ensuring variation in the advent of novel disease emergence 1‐4 …”

Section: Introductionmentioning

confidence: 99%

Survey of prevalence and investigation of predictors and staining patterns of the split upper eyelid defect in Hebridean sheep

2017

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The split upper eyelid defect (SUED) is a congenital defect of the upper eyelid thought to be exclusive to multihorned sheep. Eleven flocks with a high proportion of multihorned Hebridean sheep were visited in 2011. Statistical analysis was performed generating Pearson's chi-squared analysis, as well as (1) logistic regression, (2) ordinal logistic regression and (3) linear regression models. Four hundred and seventy-three pure-bred Hebridean sheep and one crossbred lamb were examined. Of all the multihorned animals inspected in 2011, 9.7 per cent of adults had evidence of SUED in one or more eyelids, with 17.6 per cent of lambs presented with one or more eyelid affected. Having five or more horns was protective in the linear regression model on eye-level data (p=0.045). Forward-facing horns were consistently associated with a 'worst' eye score in the eye-level data, with an odds ratio (OR) as high as 9.4 when compared with a base of backward-facing horns (p=0.002). Eyes positive for SUED were significantly more likely to be rose bengal stain-positive in all four analysis, including multilevel mixed effect ordered logistic regression (p<0.001, OR 149.3). A novel lesion was identified during the course of the study, with 3.4 per cent of lambs presented with dermoid. SUED was also identified in a crossbred animal. Further work is needed to quantify the exact cost to animals with unilateral or bilateral SUED with subtle and production cost of SUED.

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Assessment of inbreeding resulting from selection for scrapie resistance: a model for rare sheep breeds

Cited by 4 publications

References 38 publications

Prospects and challenges for the conservation of farm animal genomic resources, 2015-2025

Prospects and challenges for the conservation of farm animal genomic resources, 2015-2025

Next‐generation metrics for monitoring genetic erosion within populations of conservation concern

Survey of prevalence and investigation of predictors and staining patterns of the split upper eyelid defect in Hebridean sheep

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