Single Character Selective Model Of Major Gene And Polygene Mixed Inheritance Model Of Quantitative Trait

With the developing of statistical ideas in genetics and the spreading of computer, major gene and polygene mixed inheritance of quantitative trait is studied and applied extensively, and it has been researched seven kinds of mixed inheritance model by now. But the former study was only the identification analysis of the existing of the major gene and polygene, the identification of genetic model and the analysis of genetic effect in major gene and polygene mixed inheritance model of quantitative trait from different animal-plant. Besides, it need join non-segregating generations (parents P1 , P2 and filial generation F1 ) to estimate the environmental variance, and the selective model of this character has never been reported, bringing a certain inconvenience for breeding production.The phenotype values of the major gene and polygene mixed inheritance of quantitative trait demonstrate multimodality, showing the mixture of more than one normal distributions, that is corresponding to more than one major gene genotypes, so the selection is different from common quantitative trait in model hypothesis and analysis. Therefore, in the single character selection of major gene and polygene mixed inheritance model of quantitative trait, this paper adopts experimental design of repeated measures data, uses one-way multivariate analysis of variance to calculate the variance of major gene effect, the variance of polygene effect, environmental variance, heritability and other parameters, then according to the direct genetic gain establishes the single character selective model of major gene and polygene mixed inheritance model of quantitative traits, providing a simple selective method for breeding operators, the specific methods are as follows:Firstly, observing the major gene and polygene mixed inheritance of quantitative trait from segregating generation with equal numbers, the frequency distributions of various observation values and the average values demonstrate multimodality, so this paper uses the theory of mixed distribution to compute. In order to reduce calculation error, the frequency distribution of average values is used to compute the mixed distribution's digital features of each component distribution, thereinto, the number of the component distribution is determined by AIC, choose the number that meets the minimum value of AIC as the component number of mixed distribution, and the other parameters are estimated by EM algorithm; Secondly, because each component distribution is corresponding to a kind of major gene genotype, according to the values of the average and variance of the each component distribution, we can use the limit error of the normal distribution to plot each individual into the correspondent component distribution, namely into correspondent major gene genotype. Then we regard each major gene genotype as a treatment level of one-way analysis of variances, and the one-way multivariate analysis of variance is carried out to calculate the covariance matrix of major gene effect, covariance matrix of polygene effect, covariance matrix of environment effect and so on; At last, combining the weights of the each component distribution of mixed distribution, we can calculate the variance of major gene effect, the variance of polygene effect, environmental variance and the genetic gain of the quantitative trait. We can directly select from different populations according to the values of the genetic gains, and the selection efficiency is higher, providing convenience for breeding operators.In addition, the principle and the method of this paper is universal, it is applicable for the selection of major gene and polygene mixed inheritance of quantitative trait that exists one or more major gene locis.