基于自然群体随机交配的单个印迹QTL定位的初步研究

A Preliminary Study on Single Imprinted QTL Mapping Based on Random Mating of Natural Populations

【目的】探索基于自然群体随机交配的单个印迹QTL的定位方法,分析影响定位准确性的关键因素。【方法】若印迹QTL决定的某一性状为数量性状,假设该性状与标记之间的关系存在线性关系,可以采用最小二乘法进行印迹QTL定位和遗传参数的估计。利用计算机模拟单点模拟标记、水稻真实自然群体标记进行印迹QTL定位,比较在不同最小等位基因频率(Minor allele frequency,MAF)、不同遗传率、不同随机交配轮数下的统计功效与参数估计精度,印迹QTL的显著性采用F检验和t检验。【结果】通过模拟研究,证明该试验设计对于检测单个印迹QTL是有效的,在MAF大于5%时,印迹遗传率大于10%时,定位与遗传参数估计趋于无偏。【结论】采用自然群体随机交配产生作图群体,可以用来进行单个印迹QTL的定位,定位的结果较好,是一种有效的试验设计,为下一步进行多个印迹QTL奠定了基础。

【Objective】To explore the application of single imprinted QTL mapping based on random mating of natural populations and analyze key factors affecting the mapping accuracy.【Method】Assuming the trait determined by the imprinted QTL to be quantitative and a linear relationship between the trait and the markers existed,then the least squares method could be used to estimate the QTL mapping and genetic parameters.The imprinted QTL mapping was generated by computer simulating the single-point markers as well as a real data set of natural population markers.The statistical power and parameter estimation accuracy of different genotype frequencies,heritability rates,and random mating rounds were compared.The significance of imprinted QTLs was determined by using F-and t-tests.【Result】Through a simulation study,it was proven that the experimental design was effective in detecting a single imprinted QTL.When the MAF was greater than 5%and the imprinted heritability greater than 10%,the iQTLs positions and genetic parameters were presumably unbiased【Conclusion】Using random mating in the nature to generate mapping populations could conceivably be used to locate single-imprinted QTLs with acceptable results of localization.It seemed to be an effective design for the next step for QTL mapping.