Weller J I
Biometrics. 1986 Sep;42(3):627-40.
A method is presented to estimate the biometric parameters of a quantitative trait locus linked to a genetic marker when both loci are segregating in the F-2 generation of a cross between two inbred lines. The method, which assumes underlying normal distributions, is a combination of maximum likelihood and moments methods and uses the statistics of the genetic marker genotype samples for the quantitative trait to estimate the recombination frequency between the two loci and the means and variances of the genotypes of the quantitative trait locus. With this method, the genetic parameters of a locus affecting plant height linked to an electrophoretic marker for esterase were accurately estimated from a sample of 1596 F-2 progeny of a cross between two species of Lycopersicon (tomato). Linkage distance between the two loci was 38 map units and the effect of the quantitative trait locus was 1.6 phenotypic standard deviation units. Accurate estimates of the genetic parameters and linkage distance for populations of 2000 individuals simulated with a segregating codominant locus with an effect of 1.63 standard deviations linked to a genetic marker with .2 recombination were also derived by this method. The method is not effective in distinguishing between complete and partial linkage in samples of only 500 individuals or for quantitative loci with effects less than a phenotypic standard deviation. The method is more effective for codominant than for dominant loci.
本文提出了一种方法，用于估计与遗传标记连锁的数量性状基因座的生物统计学参数，此时两个基因座在两个近交系杂交的F2代中均处于分离状态。该方法假定基本呈正态分布，是最大似然法和矩法的结合，利用数量性状的遗传标记基因型样本的统计数据来估计两个基因座之间的重组频率以及数量性状基因座基因型的均值和方差。通过这种方法，从番茄两个品种杂交的1596个F2后代样本中，准确估计了与酯酶电泳标记连锁的影响株高的基因座的遗传参数。两个基因座之间的连锁距离为38个图距单位，数量性状基因座的效应为1.6个表型标准差单位。对于由一个效应为1.63个标准差的共显性分离基因座与一个重组率为0.2的遗传标记连锁的2000个个体的群体，通过该方法也能准确估计其遗传参数和连锁距离。该方法对于仅500个个体的样本，或对于效应小于一个表型标准差的数量基因座，在区分完全连锁和部分连锁方面效果不佳。该方法对共显性基因座比对显性基因座更有效。
