Jiang C, Zeng Z B
CIMMYT Int. Lisboa, Mexico, D.F. Mexico.
Genetica. 1997;101(1):47-58. doi: 10.1023/a:1018394410659.
Dominant phenotype of a genetic marker provides incomplete information about the marker genotype of an individual. A consequence of using this incomplete information for mapping quantitative trait loci (QTL) is that the inference of the genotype of a putative QTL flanked by a marker with dominant phenotype will depend on the genotype or phenotype of the next marker. This dependence can be extended further until a marker genotype is fully observed. A general algorithm is derived to calculate the probability distribution of the genotype of a putative QTL at a given genomic position, conditional on all observed marker phenotypes in the region with dominant and missing marker information for an individual. The algorithm is implemented for various populations stemming from two inbred lines in the context of mapping QTL. Simulation results show that if only a proportion of markers contain missing or dominant phenotypes, QTL mapping can be almost as efficient as if there were no missing information in the data. The efficiency of the analysis, however, may decrease substantially when a very large proportion of markers contain missing or dominant phenotypes and a genetic map has to be reconstructed first on the same data as well. So it is important to combine dominant markers with codominant markers in a QTL mapping study.
遗传标记的显性表型提供了关于个体标记基因型的不完整信息。使用此不完整信息进行数量性状基因座（QTL）定位的一个后果是，由具有显性表型的标记侧翼的假定QTL的基因型推断将取决于下一个标记的基因型或表型。这种依赖性可以进一步扩展，直到完全观察到标记基因型。推导了一种通用算法，用于计算给定基因组位置上假定QTL基因型的概率分布，条件是该区域中个体的所有观察到的标记表型，包括显性和缺失的标记信息。该算法在两个自交系衍生的各种群体中实现，用于QTL定位。模拟结果表明，如果只有一部分标记包含缺失或显性表型，QTL定位几乎可以与数据中没有缺失信息时一样高效。然而，当很大比例的标记包含缺失或显性表型且必须首先在相同数据上重建遗传图谱时，分析效率可能会大幅下降。因此，在QTL定位研究中将显性标记与共显性标记结合起来很重要。
