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دسترسی آزاد مقاله
1 - A Comparison of the Sensitivity of the BayesC and Genomic Best Linear Unbiased Prediction(GBLUP) Methods of Estimating Genomic Breeding Values under Different Quantitative Trait Locus(QTL) Model Assumptions
M. Shirali S.R. Miraei-Ashtiani A. Pakdel C. Haley P. Navarro R. Pong-WongThe objective of this study was to compare the accuracy of estimating and predicting breeding values using two diverse approaches, GBLUP and BayesC, using simulated data under different quantitative trait locus(QTL) effect distributions. Data were simulated with three d چکیده کاملThe objective of this study was to compare the accuracy of estimating and predicting breeding values using two diverse approaches, GBLUP and BayesC, using simulated data under different quantitative trait locus(QTL) effect distributions. Data were simulated with three different distributions for the QTL effect which were uniform, normal and gamma (1.66, 0.4). The number of QTL was assumed to be either 5, 10 or 20. In total, 9 different scenarios were generated to compare the markers estimated breeding values obtained from these scenarios using t-tests. In comparisons between GBLUP and BayesC within different scenarios for a trait of interest, the genomic estimated breeding values produced and the true breeding values in a training set were highly correlated (r>0.80), despite diverse assumptions and distributions. BayesC produced more accurate estimations than GBLUP in most simulated traits. In all scenarios, GBLUP had a consistently high accuracy independent of different distributions of QTL effects and at all numbers of QTL. BayesC produced estimates with higher accuracies in traits influenced by a low number of QTL and with gamma QTL effects distribution. In conclusion, GBLUP and BayesC had persistent high accuracies in all scenarios, although BayesC performed better in traits with low numbers of QTL and a Gamma effect distribution. پرونده مقاله -
دسترسی آزاد مقاله
2 - Serum Protein Profile of Lori-Bakhtiari Ewes in Relation to Age, Body Weight, Birth Type and Birth Season
H. Mohammadi P. Zamani S.Z. MirhoseiniSerum protein profile could be considered as a useful indicator of physiological and pathological conditions, but several factors may interfere with the interpretation. This study was conducted to evaluate serum protein fractions in association with age, body weight, bi چکیده کاملSerum protein profile could be considered as a useful indicator of physiological and pathological conditions, but several factors may interfere with the interpretation. This study was conducted to evaluate serum protein fractions in association with age, body weight, birth type and birth season in a meat-type sheep. Blood samples were randomly taken from 96 healthy Lori-Bakhtiari ewes in the Shooli breeding station in Iran. The sampled animals randomly belonged to different age, birth type, birth season and body weight groups. Total protein and other fractions were determined by Biuret and electrophoresis methods, respectively. IgG levels were measured by ELISA method. Total protein, albumin, total globulins, albumin/globulins ratio, α1, α2, β and γ globulins and IgG levels averages were 5.82, 2.35, 3.47, 0.69, 0.06, 0.42, 0.15, 2.82 and 1.56 g/dL, respectively. Total protein had high correlations with total and γ globulins, while albumin and IgG were almost independent from other fractions. Levels of serum protein fractions in adults were also independent from body weights at different ages. Serum protein profile was significantly affected by age and birth season (P<0.05), where by older ewes had lower levels of α2, γ and total globulins and higher albumin/globulin ratios. The winter-born ewes significantly had higher γ globulins levels and probably more immune system activities, compared to the spring-born ewes. Body weight and birth type did not have any significant effect on the studied serum protein fractions. This study suggested that the age and birth season should be considered for interpretation of the serum protein profiles. پرونده مقاله -
دسترسی آزاد مقاله
3 - Analysis of Test Day Milk Yield by Random Regression Models and Evaluation of Persistency in Iranian Dairy Cows
M. Elahi Torshizi A.A. Aslamenejad M.R. Nassiri H. Farhangfar J. Solkner M. Kovac G. Meszaros S. MalovrhVariace / covariance components of 227118 first lactaiom test-day milk yield records belonged to 31258 Iranian Holstein cows were estimated using nine random regression models. Afterwards, different measures of persistency based on estimation breeding value were evaluat چکیده کاملVariace / covariance components of 227118 first lactaiom test-day milk yield records belonged to 31258 Iranian Holstein cows were estimated using nine random regression models. Afterwards, different measures of persistency based on estimation breeding value were evaluated. Three functions were used to adjust fixed lactation curve: Ali and Schaeffer (AS), quadratic (LE3) and cubic (LE4) order of Legendre polynomial but for random effects, unequal order of Legendre polynomials (LE3, LE4, LE5 and Ali and Schaffer) functions were evaluated. Heterogeneous residual variance considered during days in milk and evaluation of models was based on eigenvalues and associated eigenvectors and residual variance. Model with Ali and Schaeffer function for fixed part and LE3 and LE4 for additive and permanent environmental effects was selected as the best model for random regression analysis in first parity dairy cows. The highest and lowest heritability were observed in the middle (0.29) and beginning (0.08) of lactation, respectively. Persistency measurement proposed by Cobuci (PSY1) (difference between estimation breeding value between 290 and 90 days) was preferential for using in further genetic evaluations for persistency in milk yield of Iranian Holstein cows. پرونده مقاله -
دسترسی آزاد مقاله
4 - Effects of Marker Density, Number of Quantitative Trait Loci and Heritability of Trait on Genomic Selection Accuracy
ف. علاء نوشهر س.ع. رأفت ر. ایمانی-نبئی ص. علیجانی ک. روبرت گرنیهThe success of genomic selection mainly depends on the extent of linkage disequilibrium (LD) between markers and quantitative trait loci (QTL), number of QTL and heritability (h2) of the traits. The extent of LD depends on the genetic structure of the population and mar چکیده کاملThe success of genomic selection mainly depends on the extent of linkage disequilibrium (LD) between markers and quantitative trait loci (QTL), number of QTL and heritability (h2) of the traits. The extent of LD depends on the genetic structure of the population and marker density. This study was conducted to determine the effects of marker density, level of heritability, number of QTL, and to compare the accuracy of predicting breeding values using two diverse approaches: GBLUP and BayesA using simulated data under two different distributions of the QTL effect. Thereby, three traits (milk production, carcass weight and mature body weight) were simulated with the heritability of 0.10, 0.30 and 0.50, respectively; for each ovine animal, a genome with three chromosomes, 100 cM each. Three different marker densities was considered (1000, 2000 and 3000 markers) and the number of QTL was assumed to be either 100, 200 or 300. Data were simulated with two different distributions of the QTL effect which were uniform and gamma (α=1.66 and β=0.4) the marker density, number of the QTL, the QTL effect distributions and heritability levels significantly affected the accuracy of genomic breeding values (P<0.05). The BayesA produced estimates with greater accuracies in traits influenced by a low number of the QTL and with the gamma QTL effects distribution. Based on the findings of this simulation, heritability, as well as dense marker panels, aiming to increase the level of LD between the markers and QTL, is likely to be needed for successful implementation of the genomic selection. پرونده مقاله -
دسترسی آزاد مقاله
5 - Myostatin Gene Polymorphism and Its Association with Production Traits in Western Azerbaijan Native Chickens
S. Zandi P. Zamani K. MardaniIn the present study, the polymorphism of myostatin gene (MSTN) in native chickens of Western Azerbaijan Rearing and Breeding Institute was investigated. The blood samples were collected from eighty two randomly selected hens. Genomic DNA was extracted from blood sample چکیده کاملIn the present study, the polymorphism of myostatin gene (MSTN) in native chickens of Western Azerbaijan Rearing and Breeding Institute was investigated. The blood samples were collected from eighty two randomly selected hens. Genomic DNA was extracted from blood samples and a fragment of myostatin including 599 bp in promoter and exon 1 was amplified using PCR method. Breeding values for body weight and carcass traits were predicted by univariate animal mixed model analysis, using WOMBAT software. The effects of different SSCP genotypes on breeding and phenotypic values of the studied traits were evaluated by general linear model analysis. Three different single strand conformational polymorphism(SSCP) genotypes as AA, AB and AC were identified, with frequencies of 0.244, 0.549 and 0.207, respectively. Shannon and Nei gene diversity indices and number of effective alleles in the studied population were 0.88, 0.53 and 2.2, respectively, which indicated a high diversity of the studied population. Moreover, the studied population was not in Hardy-Weinberg equilibrium. The effect of the SSCP genotypes on breeding and phenotypic values was significant only in the case of breeding value for body weight at 12 weeks of age, whereas, the AC genotype individuals, significantly (P<0.05) had the lowest breeding value for body weight at 12 weeks of age. Based on the results obtained, it could be concluded that the studied fragment of myostatin gene is polymorphic in native chickens of Azerbaijan and could be used for marker assisted selection. پرونده مقاله -
دسترسی آزاد مقاله
6 - Association between DGAT1 Genotype and Breeding Value of Milk Production Traits in Iranian Holstein Bulls
م. حسین پور مشهدی م. نصیری ن. امام جمعه کاشان ر. واعظ ترشیزیThe aim of this study was to test the genotypes effect of DGAT1 gene on breeding value in Iranian Holstein milk production traits. For this purpose, 103 semen samples of registered bulls were collected and then genotyped for partial region of DGAT1 gene. The studied tra چکیده کاملThe aim of this study was to test the genotypes effect of DGAT1 gene on breeding value in Iranian Holstein milk production traits. For this purpose, 103 semen samples of registered bulls were collected and then genotyped for partial region of DGAT1 gene. The studied traits were milk yield (MY), fat yield (FY), protein yield (PY), fat percentage (FP) and protein percentage (PP). First lactation records of 43044 dairy cattle from 2000 to 2007 were used. The PCR-RFLP method was used for genotyping DGAT1 gene. The Hardy Weinberg equilibrium for allele and genotype frequencies was analyzed with Chi-square test using PoP-Gen software. Genetic parameters of studied traits were estimated by REML method under animal model with DFREML software. The breeding value of individual was predicted by BLUP method. Different genotype effect of 97 of 103 proven bulls on breeding value of milk production traits were investigated by GLM procedure of SAS (9.1) software.The mean of breeding value of proven bulls with different genotype were compare with Duncan test. The observed genotype frequency results showed KK (0.592), KA (0.408) and AA (zero) and the allele frequency obtained was K (0.7961) and A (0.2039). The KK genotype was confirmed by sequencing method and the K allele, with long of 411 bp, was registered in gene bank of NCBI with accession number EU077528. Estimated heritability of studied traits were 0.35 (0.02), 0.33 (0.02), 0.31 (0.017), 0.28 (0.02) and 0.27 (0.016) for MY, FY, PY, FP and PP, respectively. The average breeding values of MY, FY, PY, FP and PP were estimated as: 180.2 (28.8) kg, 3.7 (1.26) kg, 2.3 (1.06) kg, -0.036 (0.014) % and -0.03 (0.01) %, respectively. The average breeding value of MY for KA and KK genotypes were 288.8 and 109.6 kg, respectively and the difference was significant (P<0.01). The average breeding values of FY in bulls for KK and KA genotypes were 5.6 kg and 0.91 kg, respectively (P>0.05). The average breeding values of PY for KA and KK genotypes were 0.025 and 5.5 kg, respectively (P<0.05). Differences between means of breeding values for FP and PP were significant (P<0.05), these values for genotype KK and KA were -0.009% and -0.067% for fat and -0.016% and -0.059% for protein, respectively. پرونده مقاله -
دسترسی آزاد مقاله
7 - تاثیر تعداد روز غیرآبستن در گاوهای هلشتاین بر رتبه بندی ژنتیکی مولدهای نر
روح الله برزه کار ناصر امام جمعه کاشان مسعود اسدی فوزی محمد چمنیباروری و تولید شیر از صفات مهم مورد استفاده در ارزیابی ژنتیکی گاوهای نر در برنامه های اصلاح نژاد دنیا هستند. لذا برای برآورد ارزش ارثی مولدهای نر ازرکوردهای ثبت شده صفات تولید و تولیدمثل دختران آنها استفاده می شود و میزان دقت برآورد برچگونگی رتبه بندی و انتخاب آنها تاثی چکیده کاملباروری و تولید شیر از صفات مهم مورد استفاده در ارزیابی ژنتیکی گاوهای نر در برنامه های اصلاح نژاد دنیا هستند. لذا برای برآورد ارزش ارثی مولدهای نر ازرکوردهای ثبت شده صفات تولید و تولیدمثل دختران آنها استفاده می شود و میزان دقت برآورد برچگونگی رتبه بندی و انتخاب آنها تاثیر دارد. هدف از این تحقیق بررسی وضعیت تولیدمثل و باروری در گله های گاو هلشتاین ایران و تاثیر زمان باروری بر تولید شیر و رتبه بندی مولدهای نر بود. برای این منظور تعداد 706653 رکورد روزآزمون زایش اول 78517 راس گاو هلشتاین در 448 گله در سال های 1370 تا 1394 استفاده شد. رابطه فنوتیبی و ژنتیکی تولید شیر270 روز و تعداد روز غیرآبستن و پارامترهای ژنتیکی آن از طریق یک مدل دام دو صفتی برآورد شد. همچنین داده ها با یک مدل رگرسیون تصادفی آنالیز و ارزش ارثی مولدهای نر پیش بینی شد. نتایج نشان داد در جمعیت مورد مطالعه 7/7 و 60 درصد گاوها در گله ها به ترتیب تا 45 و 112 روز بعد زایش آبستن شده اند و 6/54 درصد آبستنی ها در بازه زمانی بیشتر از 90 روز بوده است. وراثت پذیری تولید شیر 270 روز و تعداد روز غیرآبستن به ترتیب (016/0±)257/0 و (004/0±)0314/0 و همبستگی ژنتیکی آن (06/0±) 538/0 برآورد شد. دامنه تغییرات وراثت پذیری تولید شیر 270 روز برای گروه های مختلف 26/0-11/0 برآورد شد که تفاوت های آنها تحت تاثیر تعداد روز غیرآبستن بود. نتایج نشان داد تعداد روز غیرآبستن بر مقدار پیش بینی ارزش ارثی مولدهای نر برای صفت تولید شیر تاثیر دارد و موجب تغییر در رتبه بندی آنها می شود. لذا در برنامه های ارزیابی ژنتیکی و انتخاب باید برای افزایش دقت برآورد ارزش ارثی مولدهای نر متغیر تعداد روز غیرآبستن دختران گاوهای نر در مدل های ارزیابی ژنتیکی منظور شود. پرونده مقاله
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