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统计中系马里努阿犬3个世代系谱资料和兴奋性状测试记录,对中系马里努阿犬兴奋性状不同的选育方法进行模拟研究。利用系谱资料,F3和F4世代兴奋性状数据,估算个体育种值,依据表型和育种值数据,对F4犬群按照个体表型、家系表型、个体育种值、家系育种值进行排序,各选择35%个体,筛选其在F5代中的个体,统计分析各种选择方法后代表型和遗传进展,评测不同选择方法对中系马里努阿犬兴奋性状选育最优方法。研究结果:选择中系马里努阿犬个体育种值好于选择家系育种值好于选择家系好于选择个体表型,选择中系马里努阿犬公犬效果好于选择母犬的效果。 相似文献
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本研究以１９８７年从法国引进的泰克森商品代肉鸽作育种素材，采用现代遗传育种技术，通过家系选育法，结合个体性状，表型基因的选择，进行系统的世代选育。经过四年时间的培育，缍稳定了染色体中的性别性状遗传，达到了从乳鸽开始长毛就可鉴别雌雄的目的。 相似文献
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采用多性状动物模型BLUP和非求导约束最大似然法（MTDFREML）估计了引进罗曼蛋鸡纯系配套组合中4个品系9个性状的方差组分和遗传参数,并估计了固定效应的BLUE值和动物个体的加性遗传效应值（育种值）,分析了测定性状的世代间遗传趋势和表型趋势。结果表明,4个系各性状的遗传力基本一致,体重、蛋重以及不同周期的产蛋量之间存在显著的正相关。蛋重与产蛋量存在较强的遗传负相关。六个世代选育后,各品系蛋重、产蛋量的平均育种值均有提高,表明对产蛋量和蛋重的选择是有效的。 相似文献
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采用多性状动物模型BLUP和非求导约束最大似然法（MTDFREML）估计了引进罗曼蛋鸡纯系配套组合中4个品系9个性状的方差组分和遗传参数,并估计了固定效应的BLUE值和动物个体的加性遗传效应值（育种值）,分析了测定性状的世代间遗传趋势和表型趋势。结果表明,4个系各性状的遗传力基本一致,体重、蛋重以及不同周期的产蛋量之间存在显著的正相关。蛋重与产蛋量存在较强的遗传负相关。六个世代选育后,各品系蛋重、产蛋量的平均育种值均有提高,表明对产蛋量和蛋重的选择是有效的。 相似文献
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试验旨在进行芦花鸡H系开产性状遗传参数和育种值估计,为芦花鸡H系选育提供依据。收集芦花鸡H系2016—2020年系谱信息和开产性状表型数据,利用DMU软件以平均信息约束最大似然法（AIREML）剖分表型方差,以单性状动物模型分析各性状遗传力,以多性状动物模型分析性状间的遗传相关系数和表型相关系数,并基于系谱-加性效应模型（PBLUP＿A）对所有个体开产性状进行育种值估计,计算遗传进展。结果显示：芦花鸡H系开产日龄、开产体重和开产蛋重遗传力分别为0.42、0.40和0.27,开产日龄与开产体重、开产蛋重间的遗传相关分别为0.17、0.31,表型相关分别为0.11、0.18,开产体重和开产蛋重间遗传相关和表型相关系数分别为0.56和0.38;开产日龄、开产体重和开产蛋重年遗传进展分别为-0.014 d、1.14 g、0.018 g。结果表明：芦花鸡H系各开产性状均为中等遗传力性状,开产蛋重与开产日龄呈中等遗传正相关,与开产体重呈高遗传正相关,开产日龄与开产体重遗传相关较低,经过5个世代的选育,芦花鸡H系开产性状有了一定的遗传进展。对芦花鸡H系开产性状遗传参数和育种值的确定与分析研究结果,为... 相似文献
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应用动物模型BLUP法估计了阿尔巴斯白绒山羊种羊场1989-1998年共10个年度3 981只个体的抓绒量和体重的单性状育种值,以及这两个性状的综合育种值.在模型中考虑的固定效应有年龄效应和性别-群体-年度效应、随机效应有个体的加性效应和个体永久性环境效应.比较育种值选择与表型值选择的结果表明:①公羔依据断乳重选择与依据育种值选择的结果差异较大;②育成母羊依据表型值选择与依据综合育种值选择的结果差异极显著(P<0.01);③育成公羊依据表型值选择与依据综合育种值选择的结果差异极显著(P<0.01);④种公羊依据抓绒量和体重的表型值选择结果分别与依据各自性状育种值选择结果的秩相关均未达到显著水平(P>0.05).研究表明:内蒙古白绒山羊应用个体表型值选种存在准确性较差的缺点;动物模型BLUP法适合用于内蒙古白绒山羊的选种.并根据生产实际情况提出了一套选择种公羊的具体方法. 相似文献
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畜禽的选种选育在生产中至关重要,育种值估计是选种选育的核心。基因组选择（genomic selection,GS）是利用全基因组范围内的高密度标记估计个体基因组育种值的一种新型分子育种方法,目前已在牛、猪、鸡等畜禽育种中得到应用并取得了良好的效果。该方法可实现畜禽育种早期选择,降低测定费用,缩短世代间隔,提高育种值估计准确性,加快遗传进展。基因组选择主要是通过参考群体中每个个体的表型性状信息和单核苷酸多态性（single nucleotide polymorphism,SNP）基因型估计出每个SNP的效应值,然后测定候选群体中每个个体的SNP基因型,计算候选个体的基因组育种值,根据基因组育种值的高低对候选群体进行合理的选择。随着基因分型技术快速发展和检测成本不断降低,以及基因组选择方法不断优化,基因组选择已成为畜禽选种选育的重要手段。作者对一些常用的基因组选择方法进行了综述,比较了不同方法之间的差异,分析了基因组选择存在的问题与挑战,并展望了其在畜禽育种中的应用前景。 相似文献
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Canine hip dysplasia (CHD) is a multifactorial skeletal disorder which is very common in pedigree dogs and represents a huge concern for canine welfare. Control schemes based on selective breeding have been in operation for decades. The aim of these schemes is to reduce the impact of CHD on canine welfare by selecting for reduced radiographic evidence of CHD pathology as assessed by a variety of phenotypes. There is less information regarding the genotypic correlation between these phenotypes and the impact of CHD on canine welfare. Although the phenotypes chosen as the basis for these control schemes have displayed heritable phenotypic variation in many studies, success in achieving improvement in the phenotypes has been mixed. There is significant room for improvement in the current schemes through the use of estimated breeding values (EBVs), which can combine a dog's CHD phenotype with CHD phenotypes of relatives, other phenotypes as they are proven to be genetically correlated with CHD (especially elbow dysplasia phenotypes), and information from genetic tests for population-relevant DNA markers, as such tests become available. Additionally, breed clubs should be encouraged and assisted to formulate rational, evidenced-based breeding recommendations for CHD which suit their individual circumstances and dynamically to adjust the breeding recommendations based on continuous tracking of CHD genetic trends. These improvements can assist in safely and effectively reducing the impact of CHD on pedigree dog welfare. 相似文献
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One problem in modern dogs is a high occurrence of physical diseases, defects and disorders. Many breeds exhibit physical problems that affect individual dogs throughout life. A potential cause of these problems is inbreeding that is known to reduce the viability of individuals. We investigated the possible correlation between recent inbreeding and health problems in dogs and used studbook data from 26 breeds provided by the Swedish Kennel Club for this purpose. The pedigrees date back to the mid‐20th century and comprise 5–10 generations and 1 000–50 000 individuals per pedigree over our study period of 1980–2010. We compared levels of inbreeding and loss of genetic variation measured in relation to the number of founding animals during this period in the investigated dog breeds that we classified as ‘healthy’ (11 breeds) or ‘unhealthy’ (15) based on statistics on the extent of veterinary care obtained from Sweden's four largest insurance companies for pets. We found extensive loss of genetic variation and moderate levels of recent inbreeding in all breeds examined, but no strong indication of a difference in these parameters between healthy versus unhealthy breeds over this period. Thus, recent breeding history with respect to rate of inbreeding does not appear to be a main cause of poor health in the investigated dog breeds in Sweden. We identified both strengths and weaknesses of the dog pedigree data important to consider in future work of monitoring and conserving genetic diversity of dog breeds. 相似文献
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AIM: To estimate the heritability of the New Zealand Veterinary Association (NZVA) elbow phenotype, obtain estimated breeding values (EBV) for the worst-elbow score and estimate the genetic trends for this trait in four populous breeds of dogs, using the records from the NZVA Canine Elbow Dysplasia Scheme database (1992–2013).METHODS: Overall, 4,070 elbow records from a pedigree of 11,311 dogs were available for animals scored between 1992 and 2013. The worst elbow score between the left and right elbows was identified for each dog and used for EBV analysis. Estimates of heritability and EBV for the elbow score of dogs from German Shepherd dog, Labrador Retriever, Golden Retriever and Rottweiler breeds were obtained using restricted maximum likelihood procedures with a within-breed linear animal model. The model included the fixed effects of sex and birth year, with age at scoring as a covariable, and the random effect of animal. Genetic trends for the worst-elbow score were calculated as the regression coefficient of the EBV, weighted by reliabilities, on year of birth.RESULTS: The estimates of heritability for worst-elbow score were 0.25 (SE 0.06) in German Shepherd dogs, 0.46 (SE 0.06) in Labrador Retrievers, 0.18 (SE 0.07) in Golden Retrievers and 0.29 (SE 0.11) in Rottweilers. The genetic trend for German Shepherd dogs was ?0.0082 (SE 0.0015), for Labrador Retrievers was ?0.0016 (SE 0.0016), for Golden Retrievers was ?0.0033 (SE 0.0010) and for Rottweilers was ?0.0070 (SE 0.0023) units per annum, which were different from zero (p<0.01) in all breeds except Labrador Retrievers.CONCLUSIONS AND CLINICAL RELEVANCE: A small but favourable response to selection was achieved by three of the four breeds in the study period; during which selection for elbow traits has been largely voluntary. While the magnitude of genetic change in terms of elbow units per annum may appear small, it must be remembered that elbow scoring grades only range from 0–3. Greater improvement may be possible if compulsory screening was a requirement for pedigree breeding stock, and if greater selection pressure were applied on the basis on an individual’s EBV, rather than the worst-elbow score alone. The maintenance of an open registry, with transparency of EBV information made available to all breeders, may enhance selection intensity opportunities and potentially assist with the process and progress of breeding selection. 相似文献
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Different modes of selection in dogs were studied with a special focus on the availability of disease information. Canine hip dysplasia (CHD) in the German shepherd dog was used as an example. The study was performed using a simulation model, comparing cases when selection was based on phenotype, true or predicted breeding value, or genomic breeding value. The parameters in the simulation model were drawn from the real population data. The data on all parents and 40% of their progeny were assumed to be available for the genetic evaluation carried out by Gibbs sampling. With respect to the use of disease records on progeny, three scenarios were considered: random exclusion of disease data (no restrictions, N), general exclusion of disease data (G) and exclusion of disease data for popular sires (P). One round of selection was considered, and the response was expressed as change of mean CHD score, proportion of dogs scored as normal, proportion of dogs scored as clearly affected and true mean breeding value in progeny of popular sires in comparison with all sires. When no restrictions on data were applied, selection on breeding value was three times more efficient than when some systematic exclusion was practised. Higher selection response than in the exclusion cases was achieved by selecting on the basis of genomic breeding value and CHD score. Genomic selection would therefore be the method of choice in the future. 相似文献
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Merging pedigree databases to describe and compare mating practices and gene flow between pedigree dogs in France,Sweden and the UK 
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下载免费PDF全文 S. Wang G. Leroy S. Malm T. Lewis E. Strandberg W.F. Fikse 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2017,134(2):152-161
Merging pedigree databases across countries may improve the ability of kennel organizations to monitor genetic variability and health‐related issues of pedigree dogs. We used data provided by the Société Centrale Canine (France), Svenska Kennelklubben (Sweden) and the Kennel Club (UK) to study the feasibility of merging pedigree databases across countries and describe breeding practices and international gene flow within the following four breeds: Bullmastiff (BMA), English setter (ESE), Bernese mountain dog (BMD) and Labrador retriever (LBR). After merging the databases, genealogical parameters and founder contributions were calculated according to the birth period, breed and registration country of the dogs. Throughout the investigated period, mating between close relatives, measured as the proportion of inbred individuals (considering only two generations of pedigree), decreased or remained stable, with the exception of LBR in France. Gene flow between countries became more frequent, and the origins of populations within countries became more diverse over time. In conclusion, the potential to reduce inbreeding within purebred dog populations through exchanging breeding animals across countries was confirmed by an improved effective population size when merging populations from different countries. 相似文献
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Effects of errors in pedigree on three methods of estimating breeding value for litter size, backfat and average daily gain in swine 总被引：2，自引：0，他引：2
Estimated breeding value (EBV) was calculated based on either individual phenotype (SP), an index of individual phenotype and full- and half-sib family averages (SI) or Best Linear Unbiased Prediction (BLUP). Calculations were done with correct data or data with 5, 10, 15 or 20% of the records per generation containing pedigree errors. Traits considered were litter size (LS), backfat (BF) and average daily gain (ADG). When data were correct, BLUP resulted in an advantage in expected genetic gain over SP of 22, 7.2 or 30.8% for LS, BF and ADG, respectively, and over SI of 9.6, 3.8 or 21.4%. When sire and dam pedigrees were incorrect for 20% of the pigs each generation, genetic gain using SI was reduced by 7, 2.5 or 6.5% and genetic gain using BLUP was reduced by 9.3, 3.2 or 12.4% for LS, BF and ADG, respectively. With 20% of the pedigrees in error, the advantages in genetic gain of using BLUP over SP, the method unaffected by errors in pedigree, were 10.5, 3.8 and 14.6% for LS, BF and ADG, respectively. These results suggest that, although BLUP is affected to a greater degree by pedigree errors than SP or SI, selection of swine using BLUP still would improve response to selection over the use of SP or SI. 相似文献
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系谱是动物育种的重要信息来源,本研究旨在探究高密度SNP标记重构系谱在生产群体中的效果,填补使用高密度SNP信息重构多品种、大规模真实生产猪群的空白。本研究利用Illumina GeneSeek GGP Porcine 50K芯片对四川某猪场2017—2021年出生的1 471头曾祖代纯种杜洛克猪(n=986)和长白猪(n=485)进行分型,通过共祖片段法(common ancestor fragment method)分析上述两个品种群体内基因组亲缘关系,由此分别重构两品种群体系谱。同时选取有个体芯片分型信息及系谱记录的115头种猪,通过严格控制生产操作流程保证其系谱记录准确无误,用以评价准确性。结果表明,基于共祖片段法利用基因组信息可以同时推断多代次、品种混合的真实生产群体内个体对间的共祖片段分布情况及比例,且较状态相同片段(identical by state,IBS)能更准确的区分个体间亲缘关系,借此判断个体间亲缘关系并进一步推断家系结构。同时该方法在115头种猪的验证群体中共推断出702对亲缘关系,包括系谱记录的全部亲子关系对(n=184)、全同胞对(n=175)、半同胞关系对(n=109)和祖孙关系对(n=18),同时较记录系谱能额外推断出个体间未记录的三级亲缘关系(n=8)和四级亲缘关系(n=18)。其重构的系谱较常见三代系谱能更清晰地体现家系内个体间亲缘关系。本研究所用基于血缘同源(identity by descent,IBD)片段法(即共祖片段法)分析高密度SNP标记重构多品种群体系谱的方法可快速、简便的判断多品种混合群体的系谱正确性,可对丢失系谱的个体重构系谱,为选种选配、计算育种值及GWAS挖掘等育种工作提供基础。 相似文献
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E.M. van Grevenhof H.A.W. Hazewinkel H.C.M. Heuven 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2016,133(4):316-322
Patellar luxation (PL) is one of the major hereditary orthopaedic abnormalities observed in a variety of dog breeds. When the patellae move sideways out of the trochlear groove, this is called PL. The PL score varies between dogs from normal to very severe. Reducing the prevalence of PL by breeding could prevent surgery, thereby improve welfare. Orthopaedic specialists differentiate between normal and loose patellae, where the patellae can be moved to the edge of the trochlear groove, considering scoring loose patellae as normal in the future. Loose patellae are considered acceptable for breeding so far by the breeding organization. The aim of this study was to analyse the genetic background of PL to decide on the importance of loose patellae when breeding for healthy dogs. Data are available from two dog breeds, that is Flat‐coated Retrievers (n = 3808) and Kooiker dogs (n = 794), with a total of 4602 dogs. Results show that loose patellae indicate that dogs are genetically more susceptible to develop PL because family members of the dogs with loose patellae showed more severe PL. In addition, the estimated breeding values for dogs with loose patellae indicate that breeding values of dogs with loose patellae were worse than breeding values obtained for dogs with a normal score. Given these results, it is advised to orthopaedic specialists to continue to score loose patellae as a separate class and to dog breeders to minimize the use of dogs in breeding with a genetically higher susceptibility for PL. 相似文献