RUI: Genetic Dissection of the Reproductive Ground-Plan Hypothesis of Social Evolution

合作的动物社会是非常成功的，但他们的进化仍然没有被很好地理解。新出现的生殖基础计划假说为理解社会进化提供了一个框架，该假说认为非社会祖先的生殖调节途径在进化过程中被用于控制社会表型。根据这一假设，生殖基因网络应该管理不同群体成员的复杂专业化，以保证社会的运转。这一假说将生理和行为的调节机制与看似合理的进化情景联系在一起，导致了社会进化的统一理论。最近的数学模拟模型和行为研究表明，社会性昆虫的基本特征(生殖分工和工蚁行为的合作专业化)确实源于祖先的生殖周期。该项目将利用这些令人鼓舞的结果，以蜜蜂为实验模型，在遗传水平上对繁殖地面计划假说进行首次直接测试。工蜂表现出一系列相关的行为、生活史和生理特征，包括感官敏感度、行为成熟度、繁殖调节、觅食偏好和寿命。这种复杂的性状关联是由生殖基础计划假说预测的。特定的蜜蜂基因组区域已经被确定，它们影响行为成熟的速度和对花蜜或花粉的觅食偏好。将使用两个蜜蜂繁育系(选择用于高和低囤积花粉的行为)和两个小种(非洲蜜蜂和欧洲蜜蜂)来研究繁殖遗传结构和社会行为之间的预测联系。繁殖力将通过卵巢大小和卵巢活动来测量。对于这两个生殖性状，第一个目标是通过一系列实验杂交来表征遗传模式。接下来，将调查这些特征的基因控制是否与先前发现的影响社会行为的基因组区域有关，以及哪些其他区域具有影响力。最后，将从蜜蜂基因组序列中识别出有影响的基因组区域中的所有潜在基因，以基于位置和功能标准生成优先候选基因列表。将研究顶级候选基因的活性模式，并通过特定的基因表达操作来确定它们的功能。生殖性状和社会行为之间的遗传和功能基因重叠将支持社会进化的生殖地面计划假说，任何重叠都不会反驳它。因此，这个项目将批判性地检验对社会性的主要统一解释，这是一项具有广泛科学含义和兴趣的努力。这项研究的很大一部分将涉及互动的学生研究，特别是在本科生层面。学生将获得一流的尖端分子技术研究经验。更广泛的影响还延伸到部门、机构和区域层面。

Cooperative animal societies are extremely successful but their evolution still is not well understood. A framework for understanding social evolution is offered by the emerging reproductive ground-plan hypothesis, which suggests that the reproductive regulatory pathways of non-social ancestors were co-opted during evolution to control social phenotypes. According to this hypothesis, reproductive gene-networks should govern the complex specialization of different colony members that guarantee the functioning of the societies. The hypothesis links regulatory mechanisms of physiology and behavior to a plausible evolutionary scenario, leading to a unified theory of social evolution. Recent mathematical simulation models and behavioral studies suggest that the fundamental characteristics of social insects (reproductive division of labor and co-operative specialization of worker behavior) indeed are derived from an ancestral reproductive cycle. This project will take advantage of these encouraging results and conduct the first direct test of the reproductive ground-plan hypothesis at the genetic level, using the honey bee as experimental model. Worker honey bees show a set of correlated behavioral, life-history, and physiological traits; including sensory sensitivity, behavioral maturation, reproductive tuning, foraging preference and length of life. Such complex trait-associations are predicted by the reproductive ground-plan hypothesis. Specific honey bee genomic regions have been identified that affect the rate of behavioral maturation and foraging preference for nectar or pollen. Two breeding lines (selected for high and low pollen-hoarding behavior) and two races (Africanized and European) of honey bees will be used to investigate the predicted link between the genetic architectures of reproduction and of social behavior. Reproduction will be measured as ovary size and ovary activity. For both reproductive traits, the first goal is to characterize the inheritance pattern through a series of experimental crosses. Next, it will be investigated whether the genetic control of these traits is tied to the previously identified genomic regions that influence social behavior, and which other regions are influential. Finally, all potential genes in the influential genomic regions will be identified from the honey bee genome sequence to produce a prioritized candidate gene list based on positional and functional criteria. The activity patterns of the top candidate genes will be studied, and their function will be determined by means of specific gene expression manipulations. Genetic and functional gene overlap between reproductive traits and social behavior will support the reproductive ground-plan hypothesis of social evolution, no overlap will refute it. Thus, this project will critically test a major unifying explanation of sociality, which is an endeavor of broad scientific implication and interest. A significant portion of this research will involve interactive student research, particularly at the undergraduate level. Students will get first-class research experiences in cutting-edge molecular techniques. Broader impacts also extend to the departmental, institutional, and regional level.