RoL: FELS: EAGER: Genetic Constraints on the Increase of Organismal Complexity Over Time

在植物和动物中，出现新的专门的身体部位是罕见的。特化器官似乎起源于现有器官的特化版本，但它们的特化需要同一器官的不同副本之间的调节差异。这个项目将测试一个拟议的生命规律，即当一个生物体的整套染色体在进化过程中被复制时，多细胞生物进化中最大和最复杂的变化更容易实现。全基因组复制和身体部位数量增加之间的联系被认为可以解释早期四足动物的进化或开花植物的出现，但这些都是在数千万或数亿年前发生的，因此很难通过实验来研究。最近的一个事件是玉米出现了两种类型的花序（一组或一簇花排列在茎上），用于雄性和雌性繁殖——穗状花序和穗状花序；与玉米的近亲形成鲜明对比的是，它们只产生单一类型的花序。这项研究将在玉米和高粱上使用比较遗传学技术，以确定哪些遗传系统在开启或关闭时改变了花序类型。该项目将在UCARE和REU项目的支持下，为本科生提供有价值的培训。这个EAGER项目测试了一个假设，即玉米的特殊生殖器官的发育和进化是由一组祖先基因的特殊复制组合控制的，这是在整个基因组多倍体化过程中发生复制之前，非特化性器官的发育所必需的。多倍体玉米和非多倍体高粱中同源同源基因敲除的产生和表型特征将为同源猜想提供一个系统的测试。同源猜想是一种生命规律，它告诉我们，通过物种形成进化的基因倾向于保留功能，而通过复制产生的基因倾向于进化出相关但不相同的功能。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

In both plants and animals, the emergence of new specialized body parts is rare. Specialized organs appear to originate as specialized versions of existing organs, yet their specialization requires a divergence in regulation between different copies of the same organ. This project will test a proposed rule of life, that states that the largest and most complex changes in the evolution of multicellular organisms are easier to achieve when the entire set of chromosomes of an organism is duplicated in the course of evolution. Links between whole genome duplication and an increase in the number of body parts has been suggested to explain the evolution of early tetrapods or the emergence of flowering plants, but these are harder to study experimentally as they have occurred tens or hundreds of millions of years ago. A more recent event is the emergence in corn with two types of inflorescences (group or cluster of flowers arranged on a stem) for male and female reproduction - tassel and ear; contrasting to the situation in close relatives of maize that produce only a single type of inflorescence. This research will use comparative genetics techniques in maize and one such relative, sorghum, to identify which genetic systems, when turned on or off, change the inflorescence types. The project will provide valuable training to undergraduate students, supported by institutional UCARE and REU programs.This EAGER project tests the hypothesis that the development and evolution of specialized reproductive organs of maize are controlled by the specialized ensembles of duplicate copies of one set of ancestral genes that was required for development of non-specialized sexual organ, before it underwent a duplication in the course of the whole-genome polyploidization. Generation and phenotypic characterization of knockouts of syntenic orthologous genes in polyploidized maize and nonpolyploidized sorghum will provides a systematic test of the Ortholog Conjecture, a rule of life that tells that genes evolved by speciation tend to preserve function, whereas genes produced by duplication tend to evolve related but not identical functions.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.