Genetic dissection of trait variation between long-diverged mouse species

项目总结/摘要 生命在这个星球上进化了40亿年，生物体获得了惊人的表型。 有些，像狮子的鬃毛和蝴蝶的翅膀，以其纯粹的美丽吸引我们的注意力。其他人让我们 以一种非常不同的方式--它们与生物医学的相关性--而兴奋。生态学家已经将这些 植物和动物世界中的抗病和抗应激特性，这些特性的出现是为了解决类似的问题， 与人类患者的相似我们很想知道这些天然抗性表型的分子基础， 我们可以在生物医学的背景下设计药物来模仿它们。然而，大多数情况下，我们知道 因为它是其各自物种的定义特征，很久以前获得以适应独特的环境， 利基现在，数百万年过去了，这个物种通常已经失去了与其他地方的亲戚杂交的能力。 环境.这种生殖隔离是现有的基因型到表型映射工具的丧钟。 后者充斥着现代遗传学文献，它依赖于大量的重组后代 不同父母间的交配。这些工具在研究不能交配形成的物种时毫无用处 第一个是后裔。 我们已经开发了一种新的策略来突破这一障碍，并绘制性状变异的遗传基础 在长距离的物种之间。我们的方法从一个可行的，但不育的种间杂交开始。在这 杂交，在一个给定的基因，我们引入突变，破坏每两个等位基因轮流从两个物种 父母这些半合子突变体在背景方面是相同的，除了在靶基因， 每个菌株仅表达来自亲本之一的野生型等位基因。因此，如果半合子与 对于感兴趣的性状，我们推断它一定是因为在操纵的基因组中的功能等位基因变异。 绝佳的价钱我们开创了一个基因组规模的管道，用于这种所谓的互惠半合子测试，我们称之为 RH-seq，使用酵母作为概念验证。在目前的提议中，我们描述了将RH-seq移植到 哺乳动物细胞我们把重点放在一个很少研究的小鼠物种，M。栗，它可以再生轴突的 损伤后的中枢神经系统我们在这项开创性研究中发现的基因将作为跳板， 中风和脑外伤患者的药物设计。我们的后生动物RH-seq方法将为 真核生物物种间性状变异的遗传解剖。

PROJECT SUMMARY/ABSTRACT Over the four billion years that life has evolved on this planet, organisms have acquired amazing phenotypes. Some, like lions' manes and butterflies' wings, capture our attention by their sheer beauty. Others get us excited in a very different way—their relevance to biomedicine. Ecologists have catalogued remarkable disease and stress resistance traits in the plant and animal worlds, which have arisen to solve problems similar to those in human patients. We'd love to know the molecular basis of these natural resistance phenotypes, so that we can design drugs to mimic them in the biomedical context. However, most often, we know about a given trait because it is a defining feature of its respective species, acquired long ago to adapt to a unique niche. Now, millions of years later, the species usually has lost the ability to interbreed with relatives in other environments. And this reproductive isolation is a death knell for existing tools to map genotype to phenotype. The latter, which fill the pages of the modern genetics literature, rely on big panels of recombinant progeny from matings between distinct parents. These tools are no use in the study of species that can't mate to form progeny in the first place. We have developed a new strategy to break through this roadblock, and map the genetic basis of trait variation between long-diverged species. Our approach starts with a viable, but sterile, interspecific hybrid. In this hybrid, at a given gene, we introduce mutations to disrupt each of the two alleles in turn from the two species parents. These hemizygote mutants are identical with respect to background, except that at the target gene, each strain expresses a wild-type allele from only one of the parents. As such, if the hemizygotes differ with respect to a trait of interest, we infer that it must be because of functional allelic variation at the manipulated site. We have pioneered a genome-scale pipeline for this so-called reciprocal hemizygosity test, which we call RH-seq, using yeast as proof of concept. In the current proposal we describe experiments to port RH-seq to mammalian cells. We focus on a little-studied mouse species, M. castaneus, which can regrow axons of the central nervous system after injury. The genes we find in this pioneering study will serve as a springboard for drug design for stroke and brain trauma patients. And our metazoan RH-seq approach will pave the way for the genetic dissection of trait variation between species across Eukarya.