Molecular mechanism of natural variation and adaptation of circadian clock

 描述（由申请人提供） 由于地球自转，地球上大多数生物都适应了24小时循环的环境。生物体知道一天中的时间，并为即将到来的非生物和生物压力做好准备，并利用周围环境的预期变化。生物体的这种时间测量机制是其在自然界中生存的重要生物功能。以24小时为周期的可观察到的生物节律统称为昼夜节律，而昼夜节律的潜在分子机制称为昼夜节律钟。在不同的模式生物中，昼夜节律被认为是一种适应性特征。然而，我们仍然缺乏关于生物钟如何实现健身优势的知识。该提案中的研究人员已经确定了在北美菌株中收集的菌株与从其他大陆收集的菌株相比的离散脉孢菌物种复合体系统发育物种4b（PS4b）中的大陆特异性时钟变异，并提出了利用遗传学，基因组学，蛋白质组学，和计算生物学工具。他们将产生等位基因交换菌株，其中他们的基因型是相同的，除了 候选基因的大陆特异性等位基因。候选基因的适应度值将通过测量不同生境条件下的后代数量来测试。这项研究的成功结果将使我们了解生物体昼夜节律的局部适应如何影响生物体的适应性。

 DESCRIPTION (provided by applicant) Most living organisms on earth are adapted to a 24 hr cycling environment due to the rotation of the earth. An organism knows the time of the day and prepares the incoming abiotic and biotic stresses, and also utilizes the expected changes of ambient environment. This time-measuring mechanism in an organism is an important biological function for its survival in nature. The observable biological rhythm with about a 24 hr period is collectively called circadian rhythm, and the underlying molecular mechanism of circadian rhythm is called the circadian clock. It has been suggested in different model organisms that circadian rhythm is a fitness trait. However, we still lack knowledge in regards to how circadian clock achieves the fitness advantage. Researchers in the proposal have identified Continent-Specific-Clock-Variation in Neurospora discreta species complex Phylogenetic Species 4b (PS4b) in strains collected in North American strains in comparison to strains collected from other continents, and proposed to characterize how allelic variations of the adaptive gene causes variation of the clock phenotype to adapt to their unique habitat using genetics, genomics, proteomics, and computational biology tools. They will generate allele-swap strains where their genotype is identical, except the continent-specific allele of the candidate gene. The fitness value of the candidate gene will be tested by measuring the number of progeny under different habitat conditions. The successful outcome of the proposed study will allow us an insight on how a local adaption of circadian rhythm of an organism influences the organism's fitness.