An introduction to Adjuvant Selection
Adjuvant Selection and Adjuvant Optimization services are widely used in the search for molecular genetic markers and vaccine markers, including bacterial vaccines, DNA vaccines, cancer vaccines, etc., MAS breeding methods
MAS and QTL
The application of the principles and methods of modern quantitative genetics in pig breeding has achieved great success, and it is still an indispensable selection method for some quantitative traits with high heritability and continuous normal distribution. However, for low genetic traits, such as sow litter size, the selection response was not ideal. Therefore, animal genetic breeders can find the genetic difference of traits or the genetic markers linked with quantitative traits at the molecular genetic level, so as to realize the true genotype selection. The rapid development of molecular genetics and determination technology has greatly promoted the in-depth study of livestock genome analysis. Can know the genetic material from the nucleic acid level through the analysis of the genome, identification of gene function unit and its control mechanism and determined the phenotypic traits to ascertain the gene or closely chain to the gene genetic marker, on the basis of genotype selection or on livestock directly for marker assisted selection, and not affected by factors such as gender, time and environment. There are many methods for genome analysis. Candidate gene method and linkage analysis method are two basic methods for identifying quantitative trait loci. They use candidate genes or genetic markers and phenotypic traits for linkage analysis to identify or locate quantitative trait loci. The chain analysis method has attracted much attention up to now. It has been studied in Europe and America for several years. The candidate gene method has the advantages of strong statistical efficacy, wide application, low cost and simple operation, which is suitable for research in China at the present stage.
Stam (1986) suggests that the genome of an organism is marked through RFLP and that marker genotypes allow very accurate estimates of quantitative traits based on selection known as marker assisted selection (MAS). Lander and Thompson (1990) defined marker assisted selection, as the molecular genetic methods and artificial selection to achieve the combination of agronomic traits (agricultural traits) of the largest genetic improvement, further defined MAS by means of molecular genetics and genetic engineering, on the basis of the linkage analysis, using the modern breeding principle and method of realization of agronomic traits biggest genetic improvement.
Quantitative trait loci (QTLS) are small polygenic populations occupying a specific chromosome region. It may control an economic trait and has the potential to be closely linked to a DNA molecular marker that is easy to detect. Therefore, using molecular biology technology to detect pig DNA markers and analyze the linkage between genetic markers and important economic traits is the focus of the world's pig genetic breeding research.
MAS indirectly realizes the selection of QTL controlling a trait through the selection of genetic markers, so as to achieve the purpose of selecting the trait. Or using genetic markers to predict individual genotype values or breeding values. However, although the MAS performance is affected by the sampling and analysis methods, it is more dependent on the selected genetic markers and QTLS, and there are strict requirements for them. Molecular marker-assisted selection has provided a new way to improve the production traits with low genetic power, such as litter size. However, the precondition for effective use of molecular markers for assisted selection is that the genes controlling such traits must be precisely located. After the gene is located and cloned, the genetic law of how the local gene regulates the production phenotype or participates in the related biochemical pathway can be clarified.
The advantages of MAS are: when the linkage imbalance between the initial gene loci is large, the marker selection is more effective than the direct selection, which is very obvious when removing recessive harmful genes; Not restricted by sex, as by reproductive traits; Early selection, such as reproductive and carcass traits; Cost savings.
MAS and QTL
The application of the principles and methods of modern quantitative genetics in pig breeding has achieved great success, and it is still an indispensable selection method for some quantitative traits with high heritability and continuous normal distribution. However, for low genetic traits, such as sow litter size, the selection response was not ideal. Therefore, animal genetic breeders can find the genetic difference of traits or the genetic markers linked with quantitative traits at the molecular genetic level, so as to realize the true genotype selection. The rapid development of molecular genetics and determination technology has greatly promoted the in-depth study of livestock genome analysis. Can know the genetic material from the nucleic acid level through the analysis of the genome, identification of gene function unit and its control mechanism and determined the phenotypic traits to ascertain the gene or closely chain to the gene genetic marker, on the basis of genotype selection or on livestock directly for marker assisted selection, and not affected by factors such as gender, time and environment. There are many methods for genome analysis. Candidate gene method and linkage analysis method are two basic methods for identifying quantitative trait loci. They use candidate genes or genetic markers and phenotypic traits for linkage analysis to identify or locate quantitative trait loci. The chain analysis method has attracted much attention up to now. It has been studied in Europe and America for several years. The candidate gene method has the advantages of strong statistical efficacy, wide application, low cost and simple operation, which is suitable for research in China at the present stage.
Stam (1986) suggests that the genome of an organism is marked through RFLP and that marker genotypes allow very accurate estimates of quantitative traits based on selection known as marker assisted selection (MAS). Lander and Thompson (1990) defined marker assisted selection, as the molecular genetic methods and artificial selection to achieve the combination of agronomic traits (agricultural traits) of the largest genetic improvement, further defined MAS by means of molecular genetics and genetic engineering, on the basis of the linkage analysis, using the modern breeding principle and method of realization of agronomic traits biggest genetic improvement.
Quantitative trait loci (QTLS) are small polygenic populations occupying a specific chromosome region. It may control an economic trait and has the potential to be closely linked to a DNA molecular marker that is easy to detect. Therefore, using molecular biology technology to detect pig DNA markers and analyze the linkage between genetic markers and important economic traits is the focus of the world's pig genetic breeding research.
MAS indirectly realizes the selection of QTL controlling a trait through the selection of genetic markers, so as to achieve the purpose of selecting the trait. Or using genetic markers to predict individual genotype values or breeding values. However, although the MAS performance is affected by the sampling and analysis methods, it is more dependent on the selected genetic markers and QTLS, and there are strict requirements for them. Molecular marker-assisted selection has provided a new way to improve the production traits with low genetic power, such as litter size. However, the precondition for effective use of molecular markers for assisted selection is that the genes controlling such traits must be precisely located. After the gene is located and cloned, the genetic law of how the local gene regulates the production phenotype or participates in the related biochemical pathway can be clarified.
The advantages of MAS are: when the linkage imbalance between the initial gene loci is large, the marker selection is more effective than the direct selection, which is very obvious when removing recessive harmful genes; Not restricted by sex, as by reproductive traits; Early selection, such as reproductive and carcass traits; Cost savings.
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