THE AGING EFFECTS ASSOCIATED WITH A POLYGENIC COMPLEX

控制衰老有三个基本层面：1)近因 导致特定细胞系或组织衰老，2)调节 将细胞和组织的特定模式整合到 个人的生活史，以及3)选择的进化力量 生活史特征决定老年人的衰老模式特征 物种。在过去，我们在这三个方面都研究过控制衰老 黑腹果蝇的异常腹部(AA)综合征水平。 最近，我们将这种综合的、多层次的方法研究扩展到 与插入诱导的短发(BB)相关的衰老表型 亲缘关系很近的物种--海德氏小卷蛾。AA和BB有许多相似之处； 两者都与进入编码区的同源插入物相关联 在28S核糖体基因中，两者似乎都能诱导功能性核糖体 多线组织缺乏，两者都会导致表型似乎是 由于保幼激素酯酶活性较低，两者都具有适应性 在干燥的自然条件下，因为它们对成虫的影响 性成熟和长寿。尽管有许多相似之处，但老龄化 与AA相关的影响通过以下途径在分子水平上得到控制 未插入的28S基因的体细胞过度复制(或失败) 脂肪体的形成，即产生幼体的多线组织 荷尔蒙酯酶。相反，初步数据表明，Hydei中的BB 是通过调整插入到未插入的28S基因的数量来控制的 在种子线上。通过对这两个物种进行研究，我们不能 只了解如何在几个不同的水平上控制衰老 但我们也希望最终能回答这个问题 为什么这两个亲缘关系如此密切的物种利用如此不同的 实现相似发育的分子途径，生理和 生态方面的结果与它们的衰老模式有关。

There are three basic levels of control of aging: 1) the proximate causes leading to senesence in particular cell lines or tissues, 2) the regulatory processes that integrate the cell and tissue specific patterns into an individual's life history, and 3) the evolutionary forces that select upon life history traits to determine the aging pattern characteristic of the species. In the past we have studied the control of aging at all three levels with the abnormal abdomen (aa) syndrome in Drosophila mercatorum. Recently, we have extended this integrated, multi-level approach study the aging phenotypes associated with insertion-induced bobbed (bb) flies in the closely related species, D. hydei. Aa and bb show many similarities; both are associated with homologous inserts that go into the coding region of the 28S ribosomal genes, both seem to induce a fuctional ribosomal deficiency in polytene tissue, both lead to phenotypes that appear to be due to lower activities of juvenile hormone esterase, and both are adaptive under desiccating conditions in nature because of their effects upon adult sexual maturation and longevity. Despite these many parallels, the aging effects associated with aa are controlled at the molecular level through somatic overreplication (or its failure) of noninserted 28S genes during formation of the fat body, the polytene tissue that produces the juvenile hormone esterase. In contrast, preliminary data indicate that bb in hydei is controlled by adjusting the number of inserted to noninserted 28S genes in the germ-line. By performing our studies on both species, we can not only learn how aging is controlled at several different levels of biological organization, but we also hope to ultimately answer the question as to why two such closely related species have utilized such different molecular routes to achieve similar development, physiological and ecological ends with respect to their aging patterns.