Cui Yuehua, Wu Jianguo, Shi Chunhai, Littell Ramon C, Wu Rongling
Department of Statistics, University of Florida, Gainesville, FL 32611, USA.
Genet Res. 2006 Feb;87(1):61-71. doi: 10.1017/S0016672306007956.
Coordinated expression of embryo and endosperm tissues is required for proper seed development. The coordination among these two tissues is controlled by the interaction between multiple genes expressed in the embryo and endosperm genomes. In this article, we present a statistical model for testing whether quantitative trait loci (QTL) active in different genomes, diploid embryo and triploid endosperm, epistatically affect a trait expressed on the endosperm tissue. The maximum likelihood approach, implemented with the EM algorithm, was derived to provide the maximum likelihood estimates of the locations of embryo- and endosperm-specific QTL and their main effects and epistatic effects. This model was used in a real example for rice in which two QTL, one from the embryo genome and the other from the endosperm genome, exert a significant interaction effect on gel consistency on the endosperm. Our model has successfully detected Waxy, a candidate gene in the embryo genome known to regulate one of the major steps of amylose biosynthesis in the endosperm. This model will have great implications for agricultural and evolutionary genetic research.
种子的正常发育需要胚胎组织和胚乳组织的协调表达。这两种组织之间的协调是由胚胎基因组和胚乳基因组中表达的多个基因之间的相互作用控制的。在本文中，我们提出了一个统计模型，用于检验在不同基因组（二倍体胚胎和三倍体胚乳）中活跃的数量性状基因座（QTL）是否上位性地影响胚乳组织上表达的性状。我们推导了用EM算法实现的最大似然方法，以提供胚胎特异性QTL和胚乳特异性QTL的位置及其主效应和上位效应的最大似然估计。该模型用于水稻的一个实际例子，其中一个来自胚胎基因组的QTL和另一个来自胚乳基因组的QTL对胚乳的胶稠度产生显著的互作效应。我们的模型成功地检测到了蜡质基因，这是胚胎基因组中的一个候选基因，已知它调控胚乳中直链淀粉生物合成的一个主要步骤。该模型将对农业和进化遗传学研究具有重要意义。
