Quantitative genetics are the traits that are affected by a large number of genes (genes or alleles) that have a small cumulative effect. The environment plays a large role in determining the appearance of these traits. These traits are of great economic importance. Examples include milk production, milk fat, body weight. The improvement of these qualities depends on their precise measurement and the use of relationships and kinship among animals in the flock to be improved.
In order to improve the traits, it is necessary to estimate the genetic value of each animal in the herd of the animal to be improved. This is called the Breeding Value, which is the choice of the animals that will become fathers of the next generation. In order to estimate the educational value of the animal, we use information about the animal itself, And the use of this information and records are the result of the existence of genetic links and relationships common among these animals. For example, milk production doubled from 1965 to the present time. This is largely due to the success of the programs of selection and genetic improvement in addition to the development of the composition of the livestock and the improvement of systems of animal care and management, What is important in genetic improvement is that it is a constant improvement and is passed on from generation to generation.
Note that animals vary in their productive capacity. This difference and variation in production does not explain the superiority of the animal. Is it due to the genetic superiority of the animal or is it exposed to good environmental factors better than other animals? Therefore, this difference must be attributed to its sources.
P = G + E
Where P represents the appearance of the characteristic and can be measured (L milk, kg weight, fat ratio ... etc.), G effect of genetic factors, E effect of the environment.
Since we do not focus on the individual in the study of character but focus on a group of individuals or clans, there are differences between individuals in these characteristics and this difference or variance symbolized by the symbol σ2 and the equation:
σ2P = σ2G + σ2 E
This equation shows that the difference in the measurement of the appearance of an attribute is due to the variation in animal genotypes and the variation in the environment in which animals are exposed. These differences can be further disaggregated into:
σ2P = σ2A + σ2 D + σ2I + σ2 PE + σ2 TE
Where σ2A stands for variation in the genomic effect of genes, σ2D variation in the genetic influence of genes or interaction of alleles in the same genotype, σ2I variation in the superior effect of genes or interaction between genes at different sites, σ2PE variation in the effect of the permanent environment - prevailing climatic conditions), σ2TE variability in the temporary environment (eg nuisance - disease - drought). From this point of view, we can estimate the role of heredity in influencing the appearance of the character. Therefore, when we study the traits, we must estimate the effect of heredity on these traits and this determines the feasibility and feasibility of genetic improvement programs for these traits.
In order to improve the traits, it is necessary to estimate the genetic value of each animal in the herd of the animal to be improved. This is called the Breeding Value, which is the choice of the animals that will become fathers of the next generation. In order to estimate the educational value of the animal, we use information about the animal itself, And the use of this information and records are the result of the existence of genetic links and relationships common among these animals. For example, milk production doubled from 1965 to the present time. This is largely due to the success of the programs of selection and genetic improvement in addition to the development of the composition of the livestock and the improvement of systems of animal care and management, What is important in genetic improvement is that it is a constant improvement and is passed on from generation to generation.
Note that animals vary in their productive capacity. This difference and variation in production does not explain the superiority of the animal. Is it due to the genetic superiority of the animal or is it exposed to good environmental factors better than other animals? Therefore, this difference must be attributed to its sources.
P = G + E
Where P represents the appearance of the characteristic and can be measured (L milk, kg weight, fat ratio ... etc.), G effect of genetic factors, E effect of the environment.
Since we do not focus on the individual in the study of character but focus on a group of individuals or clans, there are differences between individuals in these characteristics and this difference or variance symbolized by the symbol σ2 and the equation:
σ2P = σ2G + σ2 E
This equation shows that the difference in the measurement of the appearance of an attribute is due to the variation in animal genotypes and the variation in the environment in which animals are exposed. These differences can be further disaggregated into:
σ2P = σ2A + σ2 D + σ2I + σ2 PE + σ2 TE
Where σ2A stands for variation in the genomic effect of genes, σ2D variation in the genetic influence of genes or interaction of alleles in the same genotype, σ2I variation in the superior effect of genes or interaction between genes at different sites, σ2PE variation in the effect of the permanent environment - prevailing climatic conditions), σ2TE variability in the temporary environment (eg nuisance - disease - drought). From this point of view, we can estimate the role of heredity in influencing the appearance of the character. Therefore, when we study the traits, we must estimate the effect of heredity on these traits and this determines the feasibility and feasibility of genetic improvement programs for these traits.
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Genetic Engineering