Do Parental Conflict and Genomic Imprinting Cause Hybrid Lethality in Mimulus?

描述（由申请人提供）：拟进行的研究将探讨亲代和子代之间的能源和资源冲突在多大程度上推动植物物种多样化。具体来说，它将研究种子致死率，这是植物杂交的一个常见结果，是否是由于母本和父本等位基因在营养资源分配给发育中的胚胎方面相互冲突的结果。这项工作将重点研究两种猴花，Mimulus nudatus和Mimulus guttatus，这两种植物在野外没有发现杂交，只能在温室中进行困难的杂交。这项工作将利用这些物种中的每一个都与第三个拟态物种具有的交叉相容性，将一个物种的基因组中的基因引入另一个物种的基因组并观察效果。这项研究将采用尖端的基因组测序技术和新的基因组数据统计分析来识别和物理定位相关物种杂交中导致种子致死的候选基因到染色体上。拟议的实验将测试，使用基因插入技术，这些基因在功能失调的种子发育中起什么因果作用。最后，本项目将研究种子中母体和父本基因拷贝是否在不同水平上表达，以及异常表达模式是否与种子致死性相关。这项工作对我们理解物种分化过程的遗传机制有重要贡献。此外，它将使我们能够表征导致植物间杂交失败的基因的功能和多样性。这项研究对我们理解驱动植物多样化的因素和尝试从现有的通常不能杂交的品系中创造新的作物品种都有意义。

DESCRIPTION (provided by applicant): The proposed research will examine the extent to which conflict over energy and resources between parent and offspring drives species diversification in plants. Specifically it will investigate whether seed lethality, which is a common outcome of hybridization in plants, results from conflicting interactions between maternal and paternal alleles over the allocation of nutritional resources to the developing embryo. This work will focus on two species of monkeyflower, Mimulus nudatus and Mimulus guttatus, which are not found to hybridize in the wild and can only be crossed with difficulty in the greenhouse. The work will take advantage of the cross compatibility that each of these species has to a third Mimulus species to introduce genes from the genome of one species into the genome of the other and observe the effect. This research will employ cutting-edge genomic sequencing techniques and novel statistical analyses of genomic data to identify and physically map candidate genes onto chromosomes that cause seed lethality in crosses between related species. The proposed experiments will test, using gene insertion techniques, what causal role these genes play in dysfunctional seed development. Finally, this project will examine whether maternal and paternal copies of genes are expressed at different levels in seeds, and whether abnormal expression patterns correlate with seed lethality. The proposed work represents an important contribution to our understanding of the genetic mechanisms underlying the process of species divergence in general. Moreover, it will enable us to characterize the function and diversity of genes causing failed hybridization between plants. This research has relevance both for our understanding of the factors driving plant diversification and for attempts to create new crop varieties from existing lines that usually cannot hybridize. PUBLIC HEALTH RELEVANCE: Genomic imprinting in mammals and plants represents a spectacular case of convergent evolution due to the shared trait of a physical connection between the developing embryo and the mother, and similar protein groups with multiple parallel actions are involved in both groups. In humans, disruptions in the normal process of genomic imprinting during development have been linked to neurological disorders, cardiovascular disease and metabolic disorders, including obesity. This research will increase our understanding of the genomic imprinting mechanisms involved in embryonic development and potentially lead to better tools for diagnosing and treating human diseases that arise from imprinting malfunction.