Kearsey M J, Farquhar A G
School of Biological Sciences, University of Birmingham, UK.
Heredity (Edinb). 1998 Feb;80 ( Pt 2):137-42. doi: 10.1046/j.1365-2540.1998.00500.x.
We have briefly reviewed the methods currently available for QTL analysis in segregating populations and summarized some of the conclusions arising from such analyses in plant populations. We show that the analytical methods locate QTL with poor precision (10-30 cM), unless the heritability of an individual QTL is high. Also the estimates of the QTL effects, particularly the dominance effects tend to be inflated because only large estimates are significant. Estimates of numbers of QTL per trait are generally low (< 8) for individual trials. This may suggest that there are few QTL but probably reflects the power of the methods. There is no large correlation between the numbers of QTL found and the amount of the variation explained. Of those cases where dominance is measurable, dominance ratios are often > 1, but seldom significantly greater. These latter cases need further analysis. Many QTL map close to candidate genes, and there is growing evidence from synteny studies of corresponding chromosome regions carrying similar QTL in different species. However, unreliability of QTL location may suggest false candidates.
我们简要回顾了目前在分离群体中进行QTL分析的可用方法，并总结了植物群体中此类分析得出的一些结论。我们表明，除非单个QTL的遗传力较高，否则分析方法定位QTL的精度较差（10 - 30 cM）。此外，QTL效应的估计值，特别是显性效应往往被夸大，因为只有大的估计值才是显著的。单个试验中每个性状的QTL数量估计通常较低（< 8）。这可能表明QTL数量较少，但可能反映了方法的功效。发现的QTL数量与所解释的变异量之间没有很大的相关性。在那些可测量显性的情况下，显性比率通常> 1，但很少显著大于1。后一种情况需要进一步分析。许多QTL定位在候选基因附近，并且来自不同物种中携带相似QTL的相应染色体区域的共线性研究的证据越来越多。然而，QTL定位的不可靠性可能表明存在错误的候选基因。
