Abstract：
Phoresy is an interspecies interaction that facilitates spatial dispersal by attaching to a more mobile species. Hitchhiking species have evolved specific traits for physical contact and successful phoresy, but the regulatory mechanisms involved in such traits and their evolution are largely unexplored. The nematode Caenorhabditis elegans displays a hitchhiking behavior known as nictation during its stress-induced developmental stage. Dauer-specific nictation behavior has an important role in natural C. elegans populations, which experience boom-and-bust population dynamics. In this study, we investigated the nictation behavior of 137 wild C. elegans strains sampled throughout the world. We identified species-wide natural variation in nictation and performed a genome-wide association mapping. We show that the variants in the promoter of nta-1, encoding a putative steroidogenic enzyme, underlie differences in nictation. This difference is due to the changes in nta-1 expression in glial cells, which implies that glial steroid metabolism regulates phoretic behavior. Population genetic analysis and geographic distribution patterns suggest that balancing selection maintained two nta-1 haplotypes that existed in ancestral C. elegans populations. Our findings contribute to further understanding of the molecular mechanism of species interaction and the maintenance of genetic diversity within natural populations.
摘要：
Phoresy是一种种间相互作用，通过附着于更具流动性的物种来促进空间分散。搭便车的物种已经进化出身体接触和成功对抗的特定特征，但是涉及这些特征及其进化的调节机制在很大程度上尚未被探索。线虫秀丽隐杆线虫在其应激诱导的发育阶段表现出一种搭便车行为，称为“顺风车”。Dauer特异性的咀嚼行为在自然秀丽隐杆线虫种群中具有重要作用，经历了繁荣与萧条的人口动态。在这项研究中,我们调查了在世界各地采样的137个野生秀丽隐杆线虫菌株的优良行为。我们确定了物种范围内的自然变异，并进行了全基因组关联作图。我们显示nta-1启动子中的变体，编码推定的类固醇生成酶，在回音方面存在差异。这种差异是由于神经胶质细胞中nta-1表达的变化，这意味着神经胶质类固醇代谢调节电泳行为。种群遗传分析和地理分布模式表明，平衡选择维持了祖先C.elegans种群中存在的两个nta-1单倍型。我们的发现有助于进一步了解物种相互作用的分子机制以及维持自然种群内的遗传多样性。
