遗传参数估计原理探讨——亲本间亲缘相关时的参数估计方法

本文通过对方差分析模型和相应的期望均方组成的分析,提出了用同胞资料估计遗传参数,当父本间、母本间及父母本间存在亲缘相关时的参数估计方法,并以实例阐明其应用方法。采用本文方法估计的遗传参数高于采用假定亲本间不相关时的常规估计方法的结果,亲本间相关越大,这种偏差也越大。计算机程序PARESTH、PARESTF为本方法推广应用提供了方便。此外,本文结论对一般的方差分析,在因素水平间相关程度能确定的情况下也是适用的。

混合模型且亲本间存在相关时的遗传力的估测

现实中的同胞资料大多同时具有两个特点:一是所有个体并非处于同一环境,二是亲本之间也非一概没有相关。据此资料估计遗传力,常规方法难免偏差。本文通过试验模型分析并运用约束最大似然法的思想,给出了解决这一问题的方法,并用实例作了应用说明。这种方法具有更广泛的适用范围。其估测值的准确程度也有很大提高,尤其是较对亲本间相关不加考虑而言。为了便于推广应用,本文还编制了两个相应的程序。

利用单元内方差分析法估计遗传参数的探讨

在遗传力的估计过程中,需将多种非遗传因素的影响从公畜间方差或者母畜间方差中剔除。在我国常使用的是盛志廉教授提出的单元内同胞相关法。本文对该法从理论上进行了更详细的证明,并将其推广到两层分类方差分析时的情况。同时还给出了当公母畜彼此间有亲缘关系时,利用单元内方差分析估计遗传力的方法。这些方法既可使遗传力的估计简便,又具有多因方差分析的功用。

Genetic Relationship Analysis of Ramie Accessions by RAPD Markers

Genetic relationship of 12 ramie varieties with different drought resistance was analysed by using RAPD.Twenty-five 10-mer random primers were used to amplify the total DMA of these varieties.The results showed that the amplified products of 12 ramie varieties could be obtained with 12 primers.The length of amplified products was 0.6-5.15 kb.Ninety bands were identified in total,of which 11 bands were common in all 12 varieties and 79 bands were polymorphic.The polymorphic bands were 87.78% of the total amplified bands.According to the result of cluster analysis,12 ramie varieties could be divided into two classes and three groups.It was found that high drought resistant varieties were clustered into different groups or subgroups in the same class,which shows near relationship among them.