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Vouraki S, Gelasakis AI, Ekateriniadou LV, Banos G, Arsenos G. Impact of polymorphisms at the PRNP locus on the performance of dairy goats reared under low-input pastoral farming systems. Small Rumin Res 2019. [DOI: 10.1016/j.smallrumres.2019.03.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Vouraki S, Gelasakis AI, Alexandri P, Boukouvala E, Ekateriniadou LV, Banos G, Arsenos G. Genetic profile of scrapie codons 146, 211 and 222 in the PRNP gene locus in three breeds of dairy goats. PLoS One 2018; 13:e0198819. [PMID: 29879210 PMCID: PMC5991713 DOI: 10.1371/journal.pone.0198819] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 05/27/2018] [Indexed: 11/29/2022] Open
Abstract
Polymorphisms at PRNP gene locus have been associated with resistance against classical scrapie in goats. Genetic selection on this gene within appropriate breeding programs may contribute to the control of the disease. The present study characterized the genetic profile of codons 146, 211 and 222 in three dairy goat breeds in Greece. A total of 766 dairy goats from seven farms were used. Animals belonged to two indigenous Greek, Eghoria (n = 264) and Skopelos (n = 287) and a foreign breed, Damascus (n = 215). Genomic DNA was extracted from blood samples from individual animals. Polymorphisms were detected in these codons using Real-Time PCR analysis and four different Custom TaqMan® SNP Genotyping Assays. Genotypic, allelic and haplotypic frequencies were calculated based on individual animal genotypes. Chi-square tests were used to examine Hardy-Weinberg equilibrium state and compare genotypic distribution across breeds. Genetic distances among the three breeds, and between these and 30 breeds reared in other countries were estimated based on haplotypic frequencies using fixation index FST with Arlequin v3.1 software; a Neighbor-Joining tree was created using PHYLIP package v3.695. Level of statistical significance was set at P = 0.01. All scrapie resistance-associated alleles (146S, 146D, 211Q and 222K) were detected in the studied population. Significant frequency differences were observed between the indigenous Greek and Damascus breeds. Alleles 222K and 146S had the highest frequency in the two indigenous and the Damascus breed, respectively (ca. 6.0%). The studied breeds shared similar haplotypic frequencies with most South Italian and Turkish breeds but differed significantly from North-Western European, Far East and some USA goat breeds. Results suggest there is adequate variation in the PRNP gene locus to support breeding programs for enhanced scrapie resistance in goats reared in Greece. Genetic comparisons among goat breeds indicate that separate breeding programs should apply to the two indigenous and the imported Damascus breeds.
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Affiliation(s)
- Sotiria Vouraki
- Laboratory of Animal Husbandry, School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Athanasios I. Gelasakis
- Veterinary Research Institute of Thessaloniki, Hellenic Agricultural Organization Demeter, Thessaloniki, Greece
| | - Panoraia Alexandri
- Laboratory of Animal Husbandry, School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Evridiki Boukouvala
- Veterinary Research Institute of Thessaloniki, Hellenic Agricultural Organization Demeter, Thessaloniki, Greece
| | - Loukia V. Ekateriniadou
- Veterinary Research Institute of Thessaloniki, Hellenic Agricultural Organization Demeter, Thessaloniki, Greece
| | - Georgios Banos
- Laboratory of Animal Husbandry, School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
- Scotland’s Rural College and The Roslin Institute, University of Edinburgh, Scotland, United Kingdom
| | - Georgios Arsenos
- Laboratory of Animal Husbandry, School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
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Li J, Erdenee S, Zhang S, Wei Z, Zhang M, Jin Y, Wu H, Chen H, Sun X, Xu H, Cai Y, Lan X. Genetic effects of PRNP gene insertion/deletion (indel) on phenotypic traits in sheep. Prion 2018; 12:42-53. [PMID: 29394137 DOI: 10.1080/19336896.2017.1405886] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Prion protein (PRNP) gene is well known for affecting mammal transmissible spongiform encephalopathies (TSE), and is also reported to regulate phenotypic traits (e.g. growth traits) in healthy ruminants. To identify the insertion/deletion (indel) variations of the PRNP gene and evaluate their effects on growth traits, 768 healthy individuals from five sheep breeds located in China and Mongolia were identified and analyzed. Herein, four novel indel polymorphisms, namely, Intron-1-insertion-7bp (I1-7bp), Intron-2-insertion-15bp (I2-15bp), Intron-2-insertion-19bp (I2-19bp), and 3' UTR-insertion-7bp (3' UTR-7bp), were found in the sheep PRNP gene. In five analyzed breeds, the minor allelic frequencies (MAF) of the above indels were in the range of 0.008 to 0.986 (I1-7bp), 0.113 to 0.336 (I2-15bp), 0.281 to 0.510 (I2-19bp), and 0.040 to 0.238 (3' UTR-7bp). Additionally, there were 15 haplotypes and the haplotype 'II2-15bp-D3'UTR-7bp-DI2-19bp-DI1-7bp' had the highest frequency, which varied from 0.464 to 0.629 in five breeds. Moreover, association analysis revealed that all novel indel polymorphisms were significantly associated with 13 different growth traits (P < 0.05). Particularly, the influences of I2-15bp on chest width (P = 0.001) in Small Tail Han sheep (ewe), 3' UTR-7bp on chest circumference (P = 0.003) in Hu sheep, and I2-19bp on tail length (P = 0.001) in Tong sheep, were highly significant (P < 0.01). These findings may be a further step toward the detection of indel-based typing within and across sheep breeds, and of promising target loci for accelerating the progress of marker-assisted selection in sheep breeding.
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Affiliation(s)
- Jie Li
- a College of Animal Science and Technology, Innovation Experimental College, Northwest A&F University , Xi'an, Shaanxi , China
| | - Sarantsetseg Erdenee
- b College of Animal Science and Technology, Northwest A&F University , Xi'an , Shaanxi , China
| | - Shaoli Zhang
- a College of Animal Science and Technology, Innovation Experimental College, Northwest A&F University , Xi'an, Shaanxi , China
| | - Zhenyu Wei
- b College of Animal Science and Technology, Northwest A&F University , Xi'an , Shaanxi , China
| | - Meng Zhang
- b College of Animal Science and Technology, Northwest A&F University , Xi'an , Shaanxi , China
| | - Yunyun Jin
- b College of Animal Science and Technology, Northwest A&F University , Xi'an , Shaanxi , China
| | - Hui Wu
- b College of Animal Science and Technology, Northwest A&F University , Xi'an , Shaanxi , China
| | - Hong Chen
- c Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University , Yangling , Shaanxi , China
| | - Xiuzhu Sun
- b College of Animal Science and Technology, Northwest A&F University , Xi'an , Shaanxi , China
| | - Hongwei Xu
- d Science Experimental Center, College of Life Science and Engineering, Northwest University for Nationalities , Chengguan District, Lanzhou City in northwest, Lanzhou , Gansu , China
| | - Yong Cai
- d Science Experimental Center, College of Life Science and Engineering, Northwest University for Nationalities , Chengguan District, Lanzhou City in northwest, Lanzhou , Gansu , China
| | - Xianyong Lan
- b College of Animal Science and Technology, Northwest A&F University , Xi'an , Shaanxi , China
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Pathogen-mediated selection in free-ranging elk populations infected by chronic wasting disease. Proc Natl Acad Sci U S A 2017; 114:12208-12212. [PMID: 29087314 DOI: 10.1073/pnas.1707807114] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pathogens can exert a large influence on the evolution of hosts via selection for alleles or genotypes that moderate pathogen virulence. Inconsistent interactions between parasites and the host genome, such as those resulting from genetic linkages and environmental stochasticity, have largely prevented observation of this process in wildlife species. We examined the prion protein gene (PRNP) in North American elk (Cervus elaphus nelsoni) populations that have been infected with chronic wasting disease (CWD), a contagious, fatal prion disease, and compared allele frequency to populations with no history of exposure to CWD. The PRNP in elk is highly conserved and a single polymorphism at codon 132 can markedly extend CWD latency when the minor leucine allele (132L) is present. We determined population exposure to CWD, genotyped 1,018 elk from five populations, and developed a hierarchical Bayesian model to examine the relationship between CWD prevalence and PRNP 132L allele frequency. Populations infected with CWD for at least 30-50 y exhibited 132L allele frequencies that were on average twice as great (range = 0.23-0.29) as those from uninfected populations (range = 0.04-0.17). Despite numerous differences between the elk populations in this study, the consistency of increase in 132L allele frequency suggests pathogen-mediated selection has occurred due to CWD. Although prior modeling work predicted that selection will continue, the potential for fitness costs of the 132L allele or new prion protein strains to arise suggest that it is prudent to assume balancing selection may prevent fixation of the 132L allele in populations with CWD.
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Abstract
Although clinical impression suggests that cerebral disorders of adult ruminants are not very common, an understanding of the common differential diagnoses is important to maintaining animal and human health. The most common causes of cerebral dysfunction are metabolic, toxic, or infectious. Many of the diseases and disorders cannot be easily differentiated based on clinical signs or antemortem diagnostic tests alone. Knowing which diseases can be easily ruled in or out, and how, will help the practitioner make case management decisions and have broader impact through recognizing index cases of emergent diseases and reducing exposure to zoonotic pathogens.
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Affiliation(s)
- John R Middleton
- Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, 900 East Campus Drive, Columbia, MO 65211, USA.
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Genetic diversity of the prion protein gene (PRNP) coding sequence in Czech sheep and evaluation of the national breeding programme for resistance to scrapie in the Czech Republic. J Appl Genet 2016; 58:111-121. [DOI: 10.1007/s13353-016-0354-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 04/18/2016] [Accepted: 05/04/2016] [Indexed: 10/21/2022]
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Martemucci G, Iamartino D, Blasi M, Selvaggi M, D'Alessandro AG. Evaluation of genetic variability within PrP genotyped sheep of endangered Italian Altamurana breed. Prev Vet Med 2016; 123:90-96. [PMID: 26708253 DOI: 10.1016/j.prevetmed.2015.11.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 11/25/2015] [Accepted: 11/27/2015] [Indexed: 11/30/2022]
Abstract
In the last few decades, there has been increased awareness of preservation and exploitation of endangered breeds for the maintenance of biodiversity, as well as the concern for diseases in sheep breeding. This study was carried out in native endangered Altamurana dairy sheep breed from Southern Italy. The Altamurana breed was considered as two populations (Alt-Cav and Alt-Cra-Zoe), based on presumed cross-breed and remarkable differences in the PrP genotypes frequencies. The genetic diversity between the two Altamurana populations (Alt-Cav and Alt-Cra-Zoe) was evaluated in comparison to three Italian dairy breeds through fourteen microsatellite markers. Both measures of genetic distance and the population structure analysis highlighted that the Alt-Cav and Alt-Cra-Zoe sheep have a particular genetic background. The estimated fixation index (FST) and the genetic Nei's distances among the populations showed a higher level of genetic differentiation for Alt-Cav than Alt-Cra-Zoe. The Bayesian clustering analysis implemented in the STRUCTURE software showed clear and distinct clusters for the two Altamurana populations, confirming the hypothesis of Alt-Cav as a genetic group well differentiated from Alt-Cra-Zoe. Alt-Cav likely can be considered as belonging to the original strain of the Altamurana breed. This findings may be used to assist the programme for conservation and selection of scrapie resistance genotypes in endangered Altamurana sheep breed.
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Affiliation(s)
- Giovanni Martemucci
- Department of Scienze Agro-Ambientali e Territoriali, University of Bari, Via G. Amendola 165/A, 70126 Bari, Italy
| | - Daniela Iamartino
- Institute of Zootechnics, Università Cattolica del S. Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; AIA-LGS Associazione Italiana Allevatori-Laboratorio di Genetica e Servizi, Via Bergamo 292, 26100 Cremona, Italy
| | - Michele Blasi
- AIA-DQA Associazione Italiana Allevatori-Dipartimento Qualità Agroalimentare, Via Tomassetti 9, 00161 Roma, Italy
| | - Maria Selvaggi
- Department of DETO, Section of Veterinary Science and Animal Production, University of Bari, Valenzano 70010, Italy
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PrP genotype frequencies and risk evaluation for scrapie in dairy sheep breeds from southern Italy. Prev Vet Med 2015; 122:318-24. [DOI: 10.1016/j.prevetmed.2015.10.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 09/30/2015] [Accepted: 10/28/2015] [Indexed: 11/23/2022]
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9
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Scientific Opinion on the scrapie situation in the EU after 10 years of monitoring and control in sheep and goats. EFSA J 2014. [DOI: 10.2903/j.efsa.2014.3781] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Williams AL, Kreeger TJ, Schumaker BA. Chronic wasting disease model of genetic selection favoring prolonged survival in Rocky Mountain elk (Cervus elaphus). Ecosphere 2014. [DOI: 10.1890/es14-00013.1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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Guan F, Song X, Li J, Wang H, Liu Y, Jiang J, Zheng H, Jiang Y. Effects of PRNP polymorphisms on sperm quality traits in Chinese Holstein bulls. JOURNAL OF APPLIED ANIMAL RESEARCH 2013. [DOI: 10.1080/09712119.2013.842486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Zhang Z, Wang R, Xu L, Yuan F, Zhou X, Yang L, Yin X, Xu B, Zhao D. Molecular cloning and sequence analysis of prion protein gene in Xiji donkey in China. Gene 2013; 529:345-50. [PMID: 23954254 DOI: 10.1016/j.gene.2013.08.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 07/22/2013] [Accepted: 08/03/2013] [Indexed: 01/20/2023]
Abstract
Prion diseases are a group of human and animal neurodegenerative disorders caused by the deposition of an abnormal isoform prion protein (PrP(Sc)) encoded by a single copy prion protein gene (PRNP). Prion disease has been reported in many herbivores but not in Equus and the species barrier might be playing a role in resistance of these species to the disease. Therefore, analysis of genotype of prion protein (PrP) in these species may help understand the transmission of the disease. Xiji donkey is a rare species of Equus not widely reared in Ningxia, China, for service, food and medicine, but its PRNP has not been studied. Based on the reported PrP sequence in GenBank we designed primers and amplified, cloned and sequenced the PRNP of Xiji donkey. The sequence analysis showed that the Xiji donkey PRNP was consisted of an open reading frame of 768 nucleotides encoding 256 amino acids. Amino acid residues unique to donkey as compared with some Equus animals, mink, cow, sheep, human, dog, sika deer, rabbit and hamster were identified. The results showed that the amino acid sequence of Xiji donkey PrP starts with the consensus sequence MVKSH, with almost identical amino acid sequence to the PrP of other Equus species in this study. Amino acid sequence analysis showed high identity within species and close relation to the PRNP of sika deer, sheep, dog, camel, cow, mink, rabbit and hamster with 83.1-99.7% identity. The results provided the PRNP data for an additional Equus species, which should be useful to the study of the prion disease pathogenesis, resistance and cross species transmission.
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Affiliation(s)
- Zhuming Zhang
- State Key Laboratories for Agrobiotechnology, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China; College of Agriculture, Ningxia University, Yinchuan 750021, China
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Expanding possibilities for intervention against small ruminant lentiviruses through genetic marker-assisted selective breeding. Viruses 2013; 5:1466-99. [PMID: 23771240 PMCID: PMC3717717 DOI: 10.3390/v5061466] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 06/01/2013] [Accepted: 06/07/2013] [Indexed: 12/25/2022] Open
Abstract
Small ruminant lentiviruses include members that infect sheep (ovine lentivirus [OvLV]; also known as ovine progressive pneumonia virus/maedi-visna virus) and goats (caprine arthritis encephalitis virus [CAEV]). Breed differences in seroprevalence and proviral concentration of OvLV had suggested a strong genetic component in susceptibility to infection by OvLV in sheep. A genetic marker test for susceptibility to OvLV has been developed recently based on the TMEM154 gene with validation data from over 2,800 sheep representing nine cohorts. While no single genotype has been shown to have complete resistance to OvLV, consistent association in thousands of sheep from multiple breeds and management conditions highlight a new strategy for intervention by selective breeding. This genetic marker-assisted selection (MAS) has the potential to be a useful addition to existing viral control measures. Further, the discovery of multiple additional genomic regions associated with susceptibility to or control of OvLV suggests that additional genetic marker tests may be developed to extend the reach of MAS in the future. This review will cover the strengths and limitations of existing data from host genetics as an intervention and outline additional questions for future genetic research in sheep, goats, small ruminant lentiviruses, and their host-pathogen interactions.
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Dobly A, Van der Heyden S, Roels S. Trends in genotype frequency resulting from breeding for resistance to classical scrapie in Belgium (2006 ˜ 2011). J Vet Sci 2013; 14:45-51. [PMID: 23388443 PMCID: PMC3615231 DOI: 10.4142/jvs.2013.14.1.45] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Accepted: 08/08/2012] [Indexed: 11/29/2022] Open
Abstract
In sheep, susceptibility to scrapie is mainly determined by codons 136, 154, and 171 of the PRNP gene. Five haplotypes are usually present (ARR, ARQ, ARH, AHQ, and VRQ). The ARR haplotype confers the greatest resistance to classical scrapie while VRQ renders animals most susceptible. In 2004, the European Union implemented a breeding program that promotes selection of the ARR haplotype while reducing the incidence of VRQ. From 2006 to 2011 in Belgium, frequency for the ARR/ARR genotypes increased from 38.3% to 63.8% (n = 6,437), the ARQ haplotype diminished from 21.1% to 12.9%, and the VRQ haplotype decreased from 2.0% to 1.7%. The status of codon 141, a determinant for atypical scrapie, was also evaluated. Out of 27 different breeds (n = 5,163), nine were abundant. The ARR/ARR frequency increased in eight of these nine major breeds. The selection program has had a major impact on the ARR haplotype frequency in Belgium. However, the occurrence of atypical scrapie represents a critical point for this program that warrants the continuous monitoring of scrapie. Additionally, genotype frequencies among the breeds varied greatly. Texel, a breed that is common in Belgium, can still be selected for due to its average ARR frequency.
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Affiliation(s)
- Alexandre Dobly
- Pathology and Prionology, Veterinary and Agrochemical Research Centre (CODA-CERVA), 1180 Brussels, Belgium
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Associations of PrP genotype with lamb production traits in three commercial breeds of British hill sheep. Animal 2012; 3:336-46. [PMID: 22444303 DOI: 10.1017/s1751731108003637] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The National Scrapie Plan (NSP) was launched in Great Britain in 2001, with the aim of eventually eradicating scrapie, a small ruminant transmissible spongiform encephalopathy, from the national sheep flock. Specifically, a selective breeding programme, the Ram Genotyping Scheme, was devised enabling pedigree ram breeders to reduce the number of scrapie-susceptible genotypes from their flocks. The effect of large-scale manipulation of PrP genotypes on commercially important traits within the sheep industry is, however, unknown. We have therefore examined production traits in a total of 43 968 lambs from 32 pedigree breeders across three British hill breeds, comprising 8163 North Country Cheviot (Hill), 21 366 Scottish Blackface and 14 439 Welsh Mountain lambs. Traits examined included: weights at birth, 8 and 20 weeks; ultrasonic fat and muscle depth, and average daily weight gain from 8 to 20 weeks. Linear mixed models were fitted for each trait, including animal (direct) genetic effects and up to three maternal effects. Potential associations with the PrP gene were assessed by fitting either PrP genotype or number of copies of individual alleles as fixed effects. A number of breed-specific significant associations between production traits and the PrP gene were found, but no consistent significant effects were detected across the three breeds. Breed-specific effects were as follows: (i) 0.37 kg higher birth weights (BWTs) in AHQ homozygous North Country Cheviot (Hill) lambs (P < 0.01); (ii) 0.16 kg higher BWTs in ARR homozygous Scottish Blackface lambs (P < 0.05); (iii) 0.5 kg higher 8-week weights in VRQ heterozygous Scottish Blackface lambs (P < 0.01); (iv) a 0.72 kg decrease in scan weight associated with homozygous ARR Welsh Mountain lambs (P < 0.01); (v) 0.51 mm higher ultrasonic muscle depths in AHQ homozygous Welsh Mountain lambs (P < 0.01); (vi) 0.48 mm lower ultrasonic muscle depths in Welsh Mountain lambs carrying one or more copies of the ARR allele (P < 0.05) and (vii) 0.2 mm higher ultrasonic fat depths in heterozygous VRQ Welsh Mountain lambs (P < 0.05). The use of a Bonferroni correction to define appropriate significance thresholds across the three datasets, which account for the large number of independent comparisons made, resulted in breed-specific comparisons, with P < 0.01 becoming significant at P0.05, and the remaining breed-specific comparisons no longer being significant. The absence of a common effect across the three breeds suggests that any true association found may be due to breed-specific alleles of neighbouring genes in linkage disequilibrium with the PrP locus.
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Robinson SJ, Samuel MD, Johnson CJ, Adams M, McKenzie DI. Emerging prion disease drives host selection in a wildlife population. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2012; 22:1050-9. [PMID: 22645831 DOI: 10.1890/11-0907.1] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Infectious diseases are increasingly recognized as an important force driving population dynamics, conservation biology, and natural selection in wildlife populations. Infectious agents have been implicated in the decline of small or endangered populations and may act to constrain population size, distribution, growth rates, or migration patterns. Further, diseases may provide selective pressures that shape the genetic diversity of populations or species. Thus, understanding disease dynamics and selective pressures from pathogens is crucial to understanding population processes, managing wildlife diseases, and conserving biological diversity. There is ample evidence that variation in the prion protein gene (PRNP) impacts host susceptibility to prion diseases. Still, little is known about how genetic differences might influence natural selection within wildlife populations. Here we link genetic variation with differential susceptibility of white-tailed deer to chronic wasting disease (CWD), with implications for fitness and disease-driven genetic selection. We developed a single nucleotide polymorphism (SNP) assay to efficiently genotype deer at the locus of interest (in the 96th codon of the PRNP gene). Then, using a Bayesian modeling approach, we found that the more susceptible genotype had over four times greater risk of CWD infection; and, once infected, deer with the resistant genotype survived 49% longer (8.25 more months). We used these epidemiological parameters in a multi-stage population matrix model to evaluate relative fitness based on genotype-specific population growth rates. The differences in disease infection and mortality rates allowed genetically resistant deer to achieve higher population growth and obtain a long-term fitness advantage, which translated into a selection coefficient of over 1% favoring the CWD-resistant genotype. This selective pressure suggests that the resistant allele could become dominant in the population within an evolutionarily short time frame. Our work provides a rare example of a quantifiable disease-driven selection process in a wildlife population, demonstrating the potential for infectious diseases to alter host populations. This will have direct bearing on the epidemiology, dynamics, and future trends in CWD transmission and spread. Understanding genotype-specific epidemiology will improve predictive models and inform management strategies for CWD-affected cervid populations.
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Affiliation(s)
- Stacie J Robinson
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Room 208 Russell Labs, 1630 Linden Drive, Madison, Wisconsin 53706, USA.
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Imran M, Mahmood S. An overview of animal prion diseases. Virol J 2011; 8:493. [PMID: 22044871 PMCID: PMC3228711 DOI: 10.1186/1743-422x-8-493] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Accepted: 11/01/2011] [Indexed: 11/10/2022] Open
Abstract
Prion diseases are transmissible neurodegenerative conditions affecting human and a wide range of animal species. The pathogenesis of prion diseases is associated with the accumulation of aggregates of misfolded conformers of host-encoded cellular prion protein (PrPC). Animal prion diseases include scrapie of sheep and goats, bovine spongiform encephalopathy (BSE) or mad cow disease, transmissible mink encephalopathy, feline spongiform encephalopathy, exotic ungulate spongiform encephalopathy, chronic wasting disease of cervids and spongiform encephalopathy of primates. Although some cases of sporadic atypical scrapie and BSE have also been reported, animal prion diseases have basically occurred via the acquisition of infection from contaminated feed or via the exposure to contaminated environment. Scrapie and chronic wasting disease are naturally sustaining epidemics. The transmission of BSE to human has caused more than 200 cases of variant Cruetzfeldt-Jacob disease and has raised serious public health concerns. The present review discusses the epidemiology, clinical neuropathology, transmissibility and genetics of animal prion diseases.
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Affiliation(s)
- Muhammad Imran
- 1Centre for Research in Endocrinology and Reproductive Sciences (CRERS), Department of Physiology and Cell Biology, University of Health Sciences (UHS), Khayaban-e-Jamia Punjab, Lahore 54600, Pakistan
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Guan F, Pan L, Li J, Tang H, Zhu C, Shi G. Polymorphisms of the prion protein gene and their effects on litter size and risk evaluation for scrapie in Chinese Hu sheep. Virus Genes 2011; 43:147-52. [PMID: 21556743 PMCID: PMC3124648 DOI: 10.1007/s11262-011-0609-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2010] [Accepted: 04/04/2011] [Indexed: 11/26/2022]
Abstract
It is well known that scrapie is a fatal, neurodegenerative disease in sheep and goat, which belongs to the group of transmissible spongiform encephalopathies (TSEs) or prion diseases. It has been confirmed that the polymorphisms of prion protein gene (PRNP) at codons 136, 154, and 171 have strong relationship with scrapie in sheep. In the present study, nine polymorphisms of PRNP at codons 136, 154, and 171 and other six loci (at codons 101, 112, 127, 137, 138, and 152) were detected in 180 Chinese Hu sheep. All the alleles at codons 136, 154, and 171 have been identified and resulted in three new genotypes. The frequencies of predominant alleles were 85% (A136), 99.40% (R154), and 37.78% (Q171), respectively. The predominant haplotype ARQ has a relatively high frequency of 57.77%. The frequencies of dominant genotypes of ARR/ARQ and ARQ/ARQ were 30 and 26.67%, respectively. Three new found genotypes named ARQ/TRK, ARQ/TRR, and TRR/TRQ had the same lower frequencies (0.56%). The relationship of PRNP genotype with scrapie risk and litter size showed that the predominant genotypes are corresponded to the risk score of R1 (1.67%), R2 (32.22%), and R3 (42.22%). Just at the first parity, the individuals with ARH/ARH genotype had significantly larger litter size than the mean value and those with ARQ/ARQ and ARR/ARQ genotypes. In short, this study provided preliminary information about alleles and genotypes of PRNP in Chinese Hu sheep. It could be concluded that Hu sheep has a low susceptibility to natural scrapie, and the predominant PRNP genotype at least has no significant effect on litter size.
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Affiliation(s)
- Feng Guan
- College of Life Sciences, China Jiliang University, Hangzhou, 310018 People’s Republic of China
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, China Jiliang University, Hangzhou, 310018 China
| | - Lei Pan
- College of Life Sciences, China Jiliang University, Hangzhou, 310018 People’s Republic of China
| | - Jie Li
- College of Life Sciences, China Jiliang University, Hangzhou, 310018 People’s Republic of China
| | - Hong Tang
- The Key Sheep Breeding and Reproduction Biotechnology Laboratory of Xinjiang Production and Construction Group, Shihezi, 832000 People’s Republic of China
| | - Cheng Zhu
- College of Life Sciences, China Jiliang University, Hangzhou, 310018 People’s Republic of China
| | - Guoqing Shi
- The Key Sheep Breeding and Reproduction Biotechnology Laboratory of Xinjiang Production and Construction Group, Shihezi, 832000 People’s Republic of China
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Genetic predisposition of some Bulgarian sheep breeds to the scrapie disease. Virus Genes 2011; 43:153-9. [PMID: 21533749 DOI: 10.1007/s11262-011-0615-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Accepted: 04/15/2011] [Indexed: 10/18/2022]
Abstract
The aim of this study is to investigate the profile of ovine PrP gene by amino acid polymorphism at codons 136, 141, 154, and 171 for determining the genetic predisposition to the Scrapie disease for the tribal sheep and rams, with different numbers and distribution in Bulgaria. Three hundred twenty four animals originating from 41 tribal herds comprising eight breeds were included in the study. DNA was isolated from blood samples specifically amplified by PCR and sequenced. The alignments of codons 136, 141, 154, and 171 were determined. Based on the sequencing, it was established that Bulgarian breeds belong to the second and third risk groups, those with low and moderate risk of Scrapie disease. Establishment of 11 genotypes in Synthetic Population Bulgarian Milk breed reveals it to have the highest risk of the Scrapie disease; moreover, the conducting of the program will be more difficult in comparison with other investigated breeds. Evidence for the internal cross breeding is the presence of the five or six genotypes in the Copper-Red Shoumen, Replian, Karakachan, and Duben Bulgarian native breeds.
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Fediaevsky A, Calavas D, Gasqui P, Moazami-Goudarzi K, Laurent P, Arsac JN, Ducrot C, Moreno C. Quantitative estimation of genetic risk for atypical scrapie in French sheep and potential consequences of the current breeding programme for resistance to scrapie on the risk of atypical scrapie. Genet Sel Evol 2010; 42:14. [PMID: 20482755 PMCID: PMC2880962 DOI: 10.1186/1297-9686-42-14] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Accepted: 05/18/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Since 2002, active surveillance programmes have detected numerous atypical scrapie (AS) and classical scrapie cases (CS) in French sheep with almost all the PrP genotypes. The aim of this study was 1) to quantify the genetic risk of AS in French sheep and to compare it with the risk of CS, 2) to quantify the risk of AS associated with the increase of the ARR allele frequency as a result of the current genetic breeding programme against CS. METHODS We obtained genotypes at codons 136, 141, 154 and 171 of the PRNP gene for representative samples of 248 AS and 245 CS cases. We used a random sample of 3,317 scrapie negative animals genotyped at codons 136, 154 and 171 and we made inferences on the position 141 by multiple imputations, using external data. To estimate the risk associated with PrP genotypes, we fitted multivariate logistic regression models and we estimated the prevalence of AS for the different genotypes. Then, we used the risk of AS estimated for the ALRR-ALRR genotype to analyse the risk of detecting an AS case in a flock homogenous for this genotype. RESULTS Genotypes most at risk for AS were those including an AFRQ or ALHQ allele while genotypes including a VLRQ allele were less commonly associated with AS. Compared to ALRQ-ALRQ, the ALRR-ALRR genotype was significantly at risk for AS and was very significantly protective for CS. The prevalence of AS among ALRR-ALRR animals was 0.6 per thousand and was not different from the prevalence in the general population. CONCLUSION In conclusion, further selection of ALRR-ALRR animals will not result in an overall increase of AS prevalence in the French sheep population although this genotype is clearly susceptible to AS. However the probability of detecting AS cases in flocks participating in genetic breeding programme against CS should be considered.
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Gubbins S, Touzeau S, Hagenaars TJ. The role of mathematical modelling in understanding the epidemiology and control of sheep transmissible spongiform encephalopathies: a review. Vet Res 2010; 41:42. [PMID: 20175963 PMCID: PMC2847197 DOI: 10.1051/vetres/2010014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2009] [Accepted: 02/19/2010] [Indexed: 11/29/2022] Open
Abstract
To deal with the incompleteness of observations and disentangle the complexities of transmission much use has been made of mathematical modelling when investigating the epidemiology of sheep transmissible spongiform encephalopathies (TSE) and, in particular, scrapie. Importantly, these modelling approaches allow the incidence of clinical disease to be related to the underlying prevalence of infection, thereby overcoming one of the major difficulties when studying these diseases. Models have been used to investigate the epidemiology of scrapie within individual flocks and at a regional level; to assess the efficacy of different control strategies, especially selective breeding programmes based on prion protein (PrP) genotype; to interpret the results of scrapie surveillance; and to inform the design of surveillance programmes. Furthermore, mathematical modelling has played an important role when assessing the risk to human health posed by the possible presence of bovine spongiform encephalopathy in sheep. Here, we review the various approaches that have been taken when developing and analysing mathematical models for the epidemiology and control of sheep TSE and assess their impact on our understanding of these diseases. We also identify areas that require further work, discuss future challenges and identify data gaps.
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Affiliation(s)
- Simon Gubbins
- Institute for Animal Health, Pirbright Laboratory, Ash Road, Pirbright, Surrey GU24 0NF, United Kingdom.
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Boulton K, Moore R, Bishop S. Associations of PrP genotype with lamb production traits in four commercial breeds of British upland and crossing sheep. Livest Sci 2010. [DOI: 10.1016/j.livsci.2009.09.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Sawalha RM, Villanueva B, Brotherstone S, Rogers PL, Lewis RM. Prediction of prion protein genotype and association of this genotype with lamb performance traits of Suffolk sheep1,2. J Anim Sci 2010; 88:428-34. [DOI: 10.2527/jas.2009-2009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Doeschl-Wilson A, Sawalha R, Gubbins S, Villanueva B. Implications of conflicting associations of the prion protein (PrP) gene with scrapie susceptibility and fitness on the persistence of scrapie. PLoS One 2009; 4:e7970. [PMID: 19956715 PMCID: PMC2776355 DOI: 10.1371/journal.pone.0007970] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Accepted: 10/21/2009] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Existing mathematical models for scrapie dynamics in sheep populations assume that the PrP gene is only associated with scrapie susceptibility and with no other fitness related traits. This assumption contrasts recent findings of PrP gene associations with post-natal lamb survival in scrapie free Scottish Blackface populations. Lambs with scrapie resistant genotypes were found to have significantly lower survival rates than those with susceptible genotypes. The present study aimed to investigate how these conflicting PrP gene associations may affect the dynamic patterns of PrP haplotype frequencies and disease prevalence. METHODOLOGY/PRINCIPAL FINDINGS A deterministic mathematical model was developed to explore how the associations between PrP genotype and both scrapie susceptibility and postnatal lamb mortality affect the prevalence of scrapie and the associated change in PrP gene frequencies in a closed flock of sheep. The model incorporates empirical evidence on epidemiological and biological characteristics of scrapie and on mortality rates induced by causes other than scrapie. The model results indicate that unfavorable associations of the scrapie resistant PrP haplotypes with post-natal lamb mortality, if sufficiently strong, can increase scrapie prevalence during an epidemic, and result in scrapie persisting in the population. The range of model parameters, for which such effects were observed, is realistic but relatively narrow. CONCLUSIONS/SIGNIFICANCE The results of the present model suggest that for most parameter combinations an unfavourable association between PrP genotype and post-natal lamb mortality does not greatly alter the dynamics of scrapie and, hence, would not have an adverse impact on a breeding programme. There were, however, a range of scenarios, narrow, but realistic, in which such an unfavourable association resulted in an increased prevalence and in the persistence of infection. Consequently, associations between PrP genotypes and fitness traits should be taken into account when designing future models and breeding programmes.
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Affiliation(s)
- Andrea Doeschl-Wilson
- Scottish Agricultural College, Sustainable Livestock Systems, Edinburgh, United Kingdom.
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Man W, Nicholls N, Woolhouse M, Lewis R, Villanueva B. Evaluating different PrP genotype selection strategies for expected severity of scrapie outbreaks and genetic progress in performance in commercial sheep. Prev Vet Med 2009; 91:161-71. [DOI: 10.1016/j.prevetmed.2009.05.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Revised: 05/20/2009] [Accepted: 05/25/2009] [Indexed: 12/01/2022]
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Sawalha RM, Bell L, Brotherstone S, White I, Wilson AJ, Villanueva B. Scrapie-resistant sheep show certain coat colour characteristics. Genet Res (Camb) 2009; 91:39-46. [PMID: 19220930 DOI: 10.1017/s0016672308009968] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Susceptibility to scrapie is known to be associated with polymorphisms at the prion protein (PrP) gene, and this association is the basis of current selective programmes implemented to control scrapie in many countries. However, these programmes might have unintended consequences for other traits that might be associated with PrP genotype. The objective of this study was to investigate the relationship between PrP genotype and coat colour characteristics in two UK native sheep breeds valued for their distinctive coat colour patterns. Coat colour pattern, darkness and spotting and PrP genotype records were available for 11 674 Badgerfaced Welsh Mountain and 2338 Shetland sheep. The data were analysed with a log-linear model using maximum likelihood. Results showed a strong significant association of PrP genotype with coat colour pattern in Badgerfaced Welsh Mountain and Shetland sheep and with the presence of white spotting in Shetland sheep. Animals with the ARR/ARR genotype (the most scrapie resistant) had higher odds of having a light dorsum and a dark abdomen than the reverse pattern. The implication of these associations is that selection to increase resistance to scrapie based only on PrP genotype could result in change in morphological diversity and affect other associated traits such as fitness.
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Affiliation(s)
- R M Sawalha
- Scottish Agricultural College, Sustainable Livestock Systems, West Mains Road, Edinburgh EH93JG, UK.
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Associations of PrP genotype with lamb production traits in three commercial breeds of British lowland sheep. Animal 2009; 3:1688-95. [DOI: 10.1017/s175173110999067x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Dawson M, Moore RC, Bishop SC. Progress and limits of PrP gene selection policy. Vet Res 2008; 39:25. [PMID: 18258168 DOI: 10.1051/vetres:2007064] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Accepted: 11/13/2007] [Indexed: 12/22/2022] Open
Abstract
Classical scrapie has proved to be a notoriously difficult disease to control due to a poor understanding of its natural history. The recognition of disease risk linkage to PrP genotype has offered the prospect of a disease control strategy, viz. genotyping and selective breeding, novel to veterinary medicine when first considered in the 1990s. The UK Spongiform Encephalopathy Advisory Committee recommended the exploitation of this approach in a voluntary, national programme to control classical scrapie and protect the public against food-borne exposure to bovine spongiform encephalopathy, should the national flock have been exposed via contaminated feed. The National Scrapie Plan for Great Britain was launched in 2001 and uptake has been widespread throughout the purebreeding sector of the sheep industry, with membership peaking at over 12 000 flocks in 2006. A total of 700 000 rams from 90 breeds have been genotyped. A comparison of ram lambs born in 2002 with those in 2006 shows evident changes in PrP genotype frequencies which are predicted to be associated with a reduction in disease risk. Various concerns have been raised regarding possible unintended consequences of widespread selection on PrP genotype, including impacts on other performance traits and possible effects on inbreeding and genetic diversity. To date, these concerns appear to be unfounded, as no consistent associations have been found with performance traits, nor are there likely to be any detectable impacts on inbreeding in mainstream breeds. Currently, semen banks have been implemented in Great Britain to store samples from animals of all common PrP genotypes, should these genotypes be required in the future. Various strategies to minimise future disease risks are discussed in the paper.
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Affiliation(s)
- Michael Dawson
- National Scrapie Plan Administration Centre, Animal Health, Worcester, WR5 2SU, UK.
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