GENETICS OF THE SELF-INCOMPATIBILITY (S-) LOCI

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 目前，我们关注的是自交不亲和的经验性方面 (S)基因座进化。自交不亲和(SI)是植物防止近亲繁殖的一种遗传机制。S基因决定了交配的特异性(谁可以与谁交配)，类似于人类的性染色体。此外，S基因座经历了与MHC基因座相似的进化力，因为两个SI MHC基因座都是自我/非自我识别的机制。 2007-2008 与Mike Hickerson(纽约州立大学皇后区)：我们的目标是开发统计上严格的计算工具来测试系统地理假说。 摘要：自达尔文时代之前，关于群落聚集的决定因素和动态以及物种多样性的历史地理性质的基本问题就一直困扰着科学界。通过估计群落内所有物种的地理历史，系统地理数据可能能够解决有争议和悬而未决的假设，解释决定群落聚集的力量。为了实现这一目标，我们正在扩展msBayes(我们发布的一个程序，用于测试系统地理假说，如物种对的同时分歧)中使用的分层近似贝叶斯计算(HABC)模型。 2007-2008：与研究生Takashi Miyake一起，我们在分子水平上描述了罂粟自交不亲和基因的多样化模式。 摘要：自交不亲和是一种允许开花植物避免自花受精的自我识别遗传系统。自交不亲和植物通常只由具有不同交配特异性的花粉授粉(S基因座)，产生强烈的多样化选择。一个种群中可能存在数十个等位基因，物种内的多态现象由来已久。然而，关于自交不亲和基因座进化动力学的经验知识目前仅来自两个系统，即茄科、玄参科和蔷薇科的基于RNase的系统和十字花科的SRK系统。我们建议通过检测罂粟科4属5种植物的S等位基因的序列多样性来表征罂粟科植物的自交不亲和性，因为罂粟科植物具有不同的自交不亲和机制。 多样化的选择创造并保持了等位基因数量、它们的序列差异和多态年龄方面的极端水平的遗传变异。多样化的选择是自然界许多重要过程的基础，包括自我识别系统和抗病基因座，如人类的MHC基因座。这项研究将重建一个以前没有被研究过的自我识别基因的多样化历史，并将提供第一次选择过程相同(配子体)但分子基础不同的自交不亲和基因的比较。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Currently, we are focusing on empirical side of self-incompatibility (S-) locus evolution. Self-incompatibility (SI) is a genetic mechanism to prevent inbreeding in plants. S-locus determines mating specificities (who can mate with whom), and analogous to sex chromosome in human. Additionally, S-locus experiences evolutionary forces similar to MHC loci because both SI MHC are mechanisms of self-/nonself-recognition. 2007-2008 With Mike Hickerson(CUNY Queens) : We aim to develop statistically rigorous computational tools to test phylogeographic hypotheses. Abstract: Fundamental questions about the determinants and dynamics of community assembly and the historically geographic nature of species diversity have been vexing the scientific community since before the times of Darwin. By estimating the geographic history of all species within a community, phylogeographic data may be able to address the controversial and unresolved hypotheses explaining the forces determining community assembly. Toward this goal, we are expanding hierarchical approximate Bayesian computation (hABC) models used in msBayes (a program which we released to test phylogeographic hypotheses such as simultaneous divergence of species pairs). 2007-2008: With graduate student: Takashi Miyake, We are characterizing the diversification pattern of self-incompatibility locus at the molecular level in poppy. Abstract: Self-incompatibility is a genetic system of self-recognition that allows flowering plants to avoid self-fertilization. Self-incompatible plants are typically fertilized only by pollen with a different mating specificity (S-locus genotype), producing strong diversifying selection. Dozens of alleles may be maintained in a single population, and polymorphism within species is ancient. However, empirical knowledge of the evolutionary dynamics of self-incompatibility loci presently comes from just two systems, the RNase-based system in Solanaceae, Scrophulariaceae and Rosaceae, and the SRK system of Brassicaceae. We propose to characterize self-incompatibility in the Papaveraceae, which has a different molecular mechanism of self-incompatibility, by examining sequence diversity of S-alleles in five species of Papaveraceae from four genera. Diversifying selection creates and maintains extreme levels of genetic variation in terms of the numbers of alleles, their sequence divergence, and the age of polymorphism. Diversifying selection underlies many important processes in nature including self-recognition systems and disease resistance loci such as the human MHC loci. This study will reconstruct the history of diversification of a self-recognition gene that has not been previously examined, and will provide the first comparison of self-incompatibility loci in which the selective process is the same (gametophytic), but the molecular basis differs.