Collaborative Research: RUI: Mathematical and empirical investigation of a reaction-diffusion system for spot formation in hybrid Mimulus

地球上的生命呈现出令人眼花缭乱的模式。它们的范围从内部图案，如脊髓中椎骨的重复，到外部图案，如斑马上的黑色色素条纹。关于这些模式可能是如何形成的，有两种想法。“位置指定”模式是由一组基因以受控的方式在特定的位置被激活而产生的。“反应-扩散”模型认为，模式可以从相互作用的基因的自组织系统中产生。根据第二个模型，每个模式成分的位置由一个基因活动水平的随机波动决定。该网络中的其他基因对第一个基因做出反应，以创造构成模式单位所需的元素。一些特征，如猴花属中的花瓣斑点，似乎取决于这两种类型的图案形成。这个花瓣-斑点系统正被用来研究位置指定和反应扩散，以及它们如何相互作用，在自然界中创造新的复杂图案。该合作项目为一名博士生和18名本科生创造了研究机会。三名高中生将从华盛顿州瓦拉瓦拉农村的一所公立学校招募，这所学校专门为不经常接触科学经验的年轻人服务。之前在Mimulus上的工作已经确定，红色花青素的花蜜引导斑点是以与反应扩散系统一致的方式形成的。铜斑潜蝇(Mimulus cupreus x M.luteus var.)花瓣裂片斑纹的发现。杂交种创造了一个独特的机会来研究(A)这种反应-扩散系统是否更普遍地解释了Mimulus中的花模式，(B)来自花瓣维管系统的位置线索是否塑造了这些模式，以及(C)与杂交相关的基因组间相互作用如何产生在两个亲本物种中都没有看到的新的表型。研究人员将首先开发一个反应-扩散模型，重建在杂交F2遗传图谱群体中观察到的花青素斑点表型的分布。他们将通过检查重组近交系群体中存在的各种纯合子基因组，并通过使用转基因操作来改变花青素调控网络中关键基因的表达，来测试这一模型。最后，他们将研究花瓣维管系统影响斑点形成位置的假说。这将通过使用数字图像分析和空间统计来测试斑点和静脉位置之间的相关性，并通过实验通过化学和转基因扰动来操纵静脉发育来测试对斑点形成的影响来实现。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Life on earth exhibits a dazzling array of patterns. These range from internal patterns, like the repetition of vertebrae in the spinal cord, to external patterns like the stripes of black pigment on a zebra. There are two ideas about how these patterns might form. The “positional specification” model is that the patterns are created by a set of genes being turned on in specific locations in a controlled fashion. The “reaction-diffusion” model is that patterns can arise from a self-organizing system of interacting genes. According to this second model, the location of each pattern component is determined by random fluctuations in one gene’s activity level. Other genes in the network respond to the first gene to create the elements needed for making a unit of the pattern. Some traits, such as petal spots in the monkeyflower genus Mimulus, appear to depend on both types of pattern formation. This petal-spot system is being used to study both positional specification and reaction-diffusion, and how they interact to create new, complex patterns in nature. The collaborative project creates research opportunities for one Ph.D. student and eighteen undergraduates. Three high school students will be recruited from a public school in rural Walla Walla, WA that specifically serves youth not routinely exposed to scientific experiences. Previous work in Mimulus has established that nectar guide spots of red anthocyanin pigment are formed in a manner consistent with a reaction-diffusion system. The discovery of elaborate spot patterns in the petal lobes of Mimulus cupreus x M. luteus var. variegatus hybrids creates a unique opportunity to examine (a) whether this reaction-diffusion system explains floral patterning in Mimulus more generally, (b) whether positional cues originating from petal vasculature shape these patterns, and (c) how the inter-genomic interactions associated with hybridization can generate novel phenotypes not seen in either parent species. The researchers will first develop a reaction-diffusion model that recreates the distribution of anthocyanin spotting phenotypes observed in a hybrid F2 genetic mapping population. They will test this model by examining the diverse sets of homozygous genotypes present in a Recombinant Inbred Line population, and by using transgenic manipulation to alter the expression of key genes in the anthocyanin regulatory network. Finally, they will investigate the hypothesis that petal vasculature influences the location of spot formation. This will be achieved by using digital image analysis and spatial statistics to test for correlations between spot and vein locations, and experimentally manipulating vein development through chemical and transgenic perturbations to test for effects on spot formation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.