Gene expression effects of heterosis and ploidy level

说明（申请人提供）：杂种优势通常在杂交个体中观察到，表现出比亲本更大的活力。杂种优势效应与多倍体效应的相互作用已被描述，并表明多倍体个体的杂种优势更强。然而，无论是在二倍体杂种优势的分子基础，也没有机制，导致观察到的与倍性水平的相互作用目前还不清楚。存在的几种遗传模型表明，杂种优势是由于有害隐性的显性互补或等位基因相互作用和超显性。但这些模型几乎世纪来都没有变过，现有的数据也无法将其清晰区分。现在可以利用工具来研究杂种优势和多倍体对全基因组表达水平的影响，测试遗传模型，并制定潜在分子机制的模型。主要集中在使用微阵列和基因表达分析在玉米，拟议的实验将使我们能够收集必要的数据，以建立一个分子模型的杂种优势。由于杂种优势对产量的影响，以及多倍体和杂种优势在许多物种进化历史中的重要因素，这些结果将对农业具有重要意义。

DESCRIPTION (provided by applicant): Heterosis is commonly observed in hybrid individuals exhibiting vigor greater either parent. Interactions between the effects of heterosis and polyploidy have been described and indicate that heterosis is stronger in polyploid individuals. However, neither the molecular basis of heterosis in diploids nor the mechanisms leading to the observed interaction with ploidy level are understood at the moment. Several genetic models exist which suggest that heterosis is due to either dominance complementation of deleterious recessives or allelic interactions and overdominance. However, these models have remained unchanged for almost a century, and the available data cannot distinguish them clearly. Tools are now available to investigate heterosis and polyploidy effects on genome-wide expression levels, to test the genetic models, and to formulate a model for the underlying molecular mechanisms. Focusing mainly on the use of microarrays and gene expression analysis in Zea mays, the proposed experiments will allow us collect the necessary data to develop a molecular model for heterosis. The results will be of great significance for agriculture because of the impact of heterosis on yield, and also forevolutionary biology as polyploidy and heterosis are important factors in the evolutionary history of many species.