“Connectedness” is an essential component of genetic evaluations. The degree of connectedness affects the accuracy of comparing estimated breeding values (EBVs) from one herd or contemporary group to the other. It c...“Connectedness” is an essential component of genetic evaluations. The degree of connectedness affects the accuracy of comparing estimated breeding values (EBVs) from one herd or contemporary group to the other. It can be measured through Connectedness Rating (CR) which is based on variances and covariance among the estimates of contemporary group effects. A computing algorithm and a computer program for estimating CR is available. The minimum required level of connectedness depends upon the size of the contemporary groups, the level of accuracy and the residual variance. About 48% CR is required to detect differences between EBVs that are greater than 20% of the standard deviation in the trait, for group sizes of about 100 animals. Higher levels are necessary for smaller group sizes and for more accurate comparisons. Breeders participating in a common genetic evaluation program should therefore exchange their superior genetics and possibly use some common testing facilities for meaningful estimates of breeding values. Maintaining a good connectedness level will make the genetic evaluation program more useful for selection of superior breeding animals and achieving faster rate of genetic progress.展开更多
The objectives of this study were to set up a new genetic evaluation procedure to predict the breeding values of Holstein herds in Heilongjiang Province of China for milk and fat production by utilizing Canadian pedig...The objectives of this study were to set up a new genetic evaluation procedure to predict the breeding values of Holstein herds in Heilongjiang Province of China for milk and fat production by utilizing Canadian pedigree and genetic evaluation information and to compare the breeding values of the sires from different countries. The data used for evaluating young sires for the Chinese Holstein population consisted of records selected from 21 herds in Heilongjiang Province. The first lactation records of 2 496 daughters collected in 1989 and 2000 were analyzed. A single-trait animal model including a fixed herd-year effect, random animal and residual effects was used by utilizing Canadian pedigree and genetic evaluation information of 5 126 sires released from the Canadian Dairy Network in August 2000. The BLUP procedure was used to evaluate all cattle in this study and the Estimated Breeding Values (EBV)for milk and fat production of 6 697 cattle (including 673 sires and 6 024 cows) were predicted. The genetic levels of the top 100 sires originated from different countries were compared. Unlike the BLUP procedure that is being used in conjunction with the single-trait sire model in Heilongjiang Province of China now, the genetic evaluation procedure used in this study not only can be used simultaneously to evaluate sires and cows but also increase the accuracy of evaluation due to using the relationships and genetic values of the Canadian evaluated sires with more daughters. The results showed that the new procedure was useful for genetic evaluation of dairy herds and the comparison of the breeding values of these sires imported from different countries showed that a significant genetic improvement has been achieved for milk production of the Heilongjiang Holstein dairy population by importing sires from foreign countries, especially from the United States due to the higher breeding values.展开更多
The first decade since the completion of the Human Genome Project has been marked with rapid development of genomic technologies and their immediate clinical applications. Genomic analysis using oligonucleotide array ...The first decade since the completion of the Human Genome Project has been marked with rapid development of genomic technologies and their immediate clinical applications. Genomic analysis using oligonucleotide array comparative genomic hybridization （aCGH） or single nucleotide polymorphism （SNP） chips has been applied to pediatric patients with developmental and intellectual disabilities （DD/ ID）, multiple congenital anomalies （MCA） and autistic spectrum disorders （ASD）. Evaluation of analytical and clinical validities of aCGH showed 〉 99% sensitivity and specificity and increased analytical resolution by higher density probe coverage. Reviews of case series, multi-center comparison and large patient-control studies demonstrated a diagnostic yield of 12%--20%; approximately 60% of these abnormalities were recurrent genomic disorders. This pediatric experience has been extended toward prenatal diagnosis. A series of reports indicated approximately 10% of pregnancies with ultrasound-detected structural anomalies and normal cytogenetic findings had genomic abnormalities, and 30% of these abnormalities were syndromic genomic disorders. Evidence-based practice guidelines and standards for implementing genomic analysis and web-delivered knowledge resources for interpreting genomic findings have been established. The progress from this technology-driven and evidence-based genomic analysis provides not only opportunities to dissect disease-causing mechanisms and develop rational therapeutic interventions but also important lessons for integrating genomic sequencing into pediatric and prenatal genetic evaluation.展开更多
Background: Porcine reproductive and respiratory syndrome(PRRS) is one of the most infectious swine diseases in the world, resulting in over 600 million dollars of economic loss in the USA alone. More recently, the US...Background: Porcine reproductive and respiratory syndrome(PRRS) is one of the most infectious swine diseases in the world, resulting in over 600 million dollars of economic loss in the USA alone. More recently, the USA swine industry has been having additional major economic losses due to the spread of porcine epidemic diarrhea(PED).However, information regarding the amount of genetic variation for response to diseases in reproductive sows is still very limited. The objectives of this study were to identify periods of infection with of PRRS virus(PRRSV) and/or PED virus(PEDV), and to estimate the impact their impact on the phenotypic and genetic reproductive performance of commercial sows.Results: Disease(PRRS or PED) was significant(P < 0.05) for all traits analyzed except for total piglets born.Heritability estimates for traits during Clean(without any disease), PRRS, and PED ranged from 0.01(number of mummies;Clean and PED) to 0.41(abortion;PED). Genetic correlations between traits within disease statuses ranged from-0.99(proportion born dead with number weaned;PRRS) to 0.99(number born dead with born alive;Clean). Within trait, between disease statuses, estimates ranged from-0.17(number weaned between PRRS and PED) to 0.99(abortion between Clean and PRRS).Conclusion: Results indicate that selection for improved performance during PRRS and PED in commercial sows is possible and would not negatively impact performance in Clean environments.展开更多
The aim of this study was to evaluate the genetic parameters of the growth performance of Takifugu rubripes.Heritabilities and genetic correlations were estimated for body weight(BW),body length(BL),total length(TL),c...The aim of this study was to evaluate the genetic parameters of the growth performance of Takifugu rubripes.Heritabilities and genetic correlations were estimated for body weight(BW),body length(BL),total length(TL),chest measurement(CM)and trunk length(TKL)of T.rubripes from measurements of progeny at 6 months and 12 months.The results showed that the heritability was 0.37 for BW6,0.19 for BL6,0.35 for TL6,0.29 for CM6,0.26 for TKL6,0.36 for BW12,0.26 for BL12,0.25 for TL12,0.31 for CM12 and 0.15 for TKL12.The range of genetic correlations estimated at 6 months was 0.025–0.725 and−0.002–0.706 at 12 months.The results indicated that genetic improvement for faster growth rate or increased body weight in cultured T.rubripes was effective.Based on selection theory,the selection strategy for traits with medium heritability is flexible.Considering that these growth traits do not reach the high level of heritability,family selection should be expected.Given positive genetic correlations among BW,BL,TL,CM,and TKL at 6 months,the five traits could be improved simultaneously through selective breeding.As there was high genetic correlation only between BW12,BL12 and TL12,and negative correlations between TKL12 and BL12 as well as between CM12 and TL12,and only BW,BL and TL at 12 months could be improved simultaneously.展开更多
Estimating genetic connectedness among herds is important for the accuracy of dairy cattle genetic evaluation. When selecting between animals raised in different herds, the accuracy of their genetic evaluations can be...Estimating genetic connectedness among herds is important for the accuracy of dairy cattle genetic evaluation. When selecting between animals raised in different herds, the accuracy of their genetic evaluations can be influenced by the degree of connectedness among these herds. In this study, two methods were used to measure genetic connectedness, CR （genetic connectedness rating ） and GLt （total number of direct genetic links between group）, among herds from Beijing, Shanghai, and Tianjin. Genetic connectedness between the herds from Beijing and Tianjin was 23.95%, between Beijing and Shanghai was 17. 10%, and between Shanghai and Tianjin it was 14.28%. Genetic connectedness between herds from Beijing and Tianjin was the highest and that between Shanghai and Tianjin was the lowest. The correlation coefficient for the two methods was 0. 808. Some suggestions for improved genetic evaluation of dairy cattle were also discussed.展开更多
Advances in molecular biotechnology have introduced new generations of molecular markers for use in the genetic improvement of farm animals. Consequently, more accurate genetic information can be obtained to better un...Advances in molecular biotechnology have introduced new generations of molecular markers for use in the genetic improvement of farm animals. Consequently, more accurate genetic information can be obtained to better understand existing animal genetic resources. This review gives a brief summary on the development of genetic markers including both the classical genetic markers and more advanced DNA-based molecular markers. This review will help us better understand the characteristics of different genetic markers and the genetic diversity of animal genetic resources.展开更多
文摘“Connectedness” is an essential component of genetic evaluations. The degree of connectedness affects the accuracy of comparing estimated breeding values (EBVs) from one herd or contemporary group to the other. It can be measured through Connectedness Rating (CR) which is based on variances and covariance among the estimates of contemporary group effects. A computing algorithm and a computer program for estimating CR is available. The minimum required level of connectedness depends upon the size of the contemporary groups, the level of accuracy and the residual variance. About 48% CR is required to detect differences between EBVs that are greater than 20% of the standard deviation in the trait, for group sizes of about 100 animals. Higher levels are necessary for smaller group sizes and for more accurate comparisons. Breeders participating in a common genetic evaluation program should therefore exchange their superior genetics and possibly use some common testing facilities for meaningful estimates of breeding values. Maintaining a good connectedness level will make the genetic evaluation program more useful for selection of superior breeding animals and achieving faster rate of genetic progress.
文摘The objectives of this study were to set up a new genetic evaluation procedure to predict the breeding values of Holstein herds in Heilongjiang Province of China for milk and fat production by utilizing Canadian pedigree and genetic evaluation information and to compare the breeding values of the sires from different countries. The data used for evaluating young sires for the Chinese Holstein population consisted of records selected from 21 herds in Heilongjiang Province. The first lactation records of 2 496 daughters collected in 1989 and 2000 were analyzed. A single-trait animal model including a fixed herd-year effect, random animal and residual effects was used by utilizing Canadian pedigree and genetic evaluation information of 5 126 sires released from the Canadian Dairy Network in August 2000. The BLUP procedure was used to evaluate all cattle in this study and the Estimated Breeding Values (EBV)for milk and fat production of 6 697 cattle (including 673 sires and 6 024 cows) were predicted. The genetic levels of the top 100 sires originated from different countries were compared. Unlike the BLUP procedure that is being used in conjunction with the single-trait sire model in Heilongjiang Province of China now, the genetic evaluation procedure used in this study not only can be used simultaneously to evaluate sires and cows but also increase the accuracy of evaluation due to using the relationships and genetic values of the Canadian evaluated sires with more daughters. The results showed that the new procedure was useful for genetic evaluation of dairy herds and the comparison of the breeding values of these sires imported from different countries showed that a significant genetic improvement has been achieved for milk production of the Heilongjiang Holstein dairy population by importing sires from foreign countries, especially from the United States due to the higher breeding values.
基金supported in part by fellowship award from the China Scholarship Council to Yuan Wei
文摘The first decade since the completion of the Human Genome Project has been marked with rapid development of genomic technologies and their immediate clinical applications. Genomic analysis using oligonucleotide array comparative genomic hybridization （aCGH） or single nucleotide polymorphism （SNP） chips has been applied to pediatric patients with developmental and intellectual disabilities （DD/ ID）, multiple congenital anomalies （MCA） and autistic spectrum disorders （ASD）. Evaluation of analytical and clinical validities of aCGH showed 〉 99% sensitivity and specificity and increased analytical resolution by higher density probe coverage. Reviews of case series, multi-center comparison and large patient-control studies demonstrated a diagnostic yield of 12%--20%; approximately 60% of these abnormalities were recurrent genomic disorders. This pediatric experience has been extended toward prenatal diagnosis. A series of reports indicated approximately 10% of pregnancies with ultrasound-detected structural anomalies and normal cytogenetic findings had genomic abnormalities, and 30% of these abnormalities were syndromic genomic disorders. Evidence-based practice guidelines and standards for implementing genomic analysis and web-delivered knowledge resources for interpreting genomic findings have been established. The progress from this technology-driven and evidence-based genomic analysis provides not only opportunities to dissect disease-causing mechanisms and develop rational therapeutic interventions but also important lessons for integrating genomic sequencing into pediatric and prenatal genetic evaluation.
文摘Background: Porcine reproductive and respiratory syndrome(PRRS) is one of the most infectious swine diseases in the world, resulting in over 600 million dollars of economic loss in the USA alone. More recently, the USA swine industry has been having additional major economic losses due to the spread of porcine epidemic diarrhea(PED).However, information regarding the amount of genetic variation for response to diseases in reproductive sows is still very limited. The objectives of this study were to identify periods of infection with of PRRS virus(PRRSV) and/or PED virus(PEDV), and to estimate the impact their impact on the phenotypic and genetic reproductive performance of commercial sows.Results: Disease(PRRS or PED) was significant(P < 0.05) for all traits analyzed except for total piglets born.Heritability estimates for traits during Clean(without any disease), PRRS, and PED ranged from 0.01(number of mummies;Clean and PED) to 0.41(abortion;PED). Genetic correlations between traits within disease statuses ranged from-0.99(proportion born dead with number weaned;PRRS) to 0.99(number born dead with born alive;Clean). Within trait, between disease statuses, estimates ranged from-0.17(number weaned between PRRS and PED) to 0.99(abortion between Clean and PRRS).Conclusion: Results indicate that selection for improved performance during PRRS and PED in commercial sows is possible and would not negatively impact performance in Clean environments.
基金The National Key R&D Program of China under contract No.2018YFD0900102the Key Research and Development Plan of Nation under contract No.2018YFD0900301+2 种基金the AoShan Talents Cultivation Program Supported by Pilot National Laboratory for Marine Science and Technology(Qingdao)under contract No.2017ASTCP-OS04the Earmarked Fund for the Modern AgroIndustry Technology Research System under contract No.CARS-47-G01the Central Public-interest Scientific Institution Basal Research Fund under contract No.2020TD25.
文摘The aim of this study was to evaluate the genetic parameters of the growth performance of Takifugu rubripes.Heritabilities and genetic correlations were estimated for body weight(BW),body length(BL),total length(TL),chest measurement(CM)and trunk length(TKL)of T.rubripes from measurements of progeny at 6 months and 12 months.The results showed that the heritability was 0.37 for BW6,0.19 for BL6,0.35 for TL6,0.29 for CM6,0.26 for TKL6,0.36 for BW12,0.26 for BL12,0.25 for TL12,0.31 for CM12 and 0.15 for TKL12.The range of genetic correlations estimated at 6 months was 0.025–0.725 and−0.002–0.706 at 12 months.The results indicated that genetic improvement for faster growth rate or increased body weight in cultured T.rubripes was effective.Based on selection theory,the selection strategy for traits with medium heritability is flexible.Considering that these growth traits do not reach the high level of heritability,family selection should be expected.Given positive genetic correlations among BW,BL,TL,CM,and TKL at 6 months,the five traits could be improved simultaneously through selective breeding.As there was high genetic correlation only between BW12,BL12 and TL12,and negative correlations between TKL12 and BL12 as well as between CM12 and TL12,and only BW,BL and TL at 12 months could be improved simultaneously.
文摘Estimating genetic connectedness among herds is important for the accuracy of dairy cattle genetic evaluation. When selecting between animals raised in different herds, the accuracy of their genetic evaluations can be influenced by the degree of connectedness among these herds. In this study, two methods were used to measure genetic connectedness, CR （genetic connectedness rating ） and GLt （total number of direct genetic links between group）, among herds from Beijing, Shanghai, and Tianjin. Genetic connectedness between the herds from Beijing and Tianjin was 23.95%, between Beijing and Shanghai was 17. 10%, and between Shanghai and Tianjin it was 14.28%. Genetic connectedness between herds from Beijing and Tianjin was the highest and that between Shanghai and Tianjin was the lowest. The correlation coefficient for the two methods was 0. 808. Some suggestions for improved genetic evaluation of dairy cattle were also discussed.
基金supported by National High Technology and Science Development Plan of China(No.2011AA100302)Program for New Century Excellent Talents in University(No.NCET-11-0480)Program for Changjiang Scholar and Innovation Research Team in University(IRT1191)and project(CARS-41-K01)
文摘Advances in molecular biotechnology have introduced new generations of molecular markers for use in the genetic improvement of farm animals. Consequently, more accurate genetic information can be obtained to better understand existing animal genetic resources. This review gives a brief summary on the development of genetic markers including both the classical genetic markers and more advanced DNA-based molecular markers. This review will help us better understand the characteristics of different genetic markers and the genetic diversity of animal genetic resources.
