AGING EFFECTS ASSOCIATED WITH A POLYGENIC COMPLEX

控制衰老有三个基本层面：1)近端 导致特定细胞系或组织衰老的原因， 2)产生完整生活史的调控过程， 3)根据生活史特征选择的进化力量 以确定在该物种中发现的衰老模式。我们一直在 能够在所有三个层次上研究衰老的控制 黑腹果蝇和黑腹果蝇的腹部异常综合征 海德氏假丝酵母菌插入诱导的短臂综合征。两者都有 综合征是由插入失活的大的 X染色体上发现的28S核糖体基因的比例。 然而，衰老效应是通过控制躯体来调节的。 插入基因和非插入基因在Mercatorum中的复制， 而插入基因比例的数量变化 似乎调节了海德氏假丝酵母的综合症。两种症状都是 与幼虫发育时间减慢有关，增加 成虫早期繁殖力强，成虫寿命下降。这些 综合征在自然环境条件下是适应的 导致年轻的成人年龄结构。 将研究再生障碍性贫血的遗传结构，最初的 重点关注体细胞复制和数量的影响 插入比例在老化表型上的变化。常染色体 修饰物也将被分离和表征，它将 已确定这些修饰剂是否可以改变多效性的模式。 Y基因对雄性AA基因表达的调控 将对染色体进行研究，特别强调 Y连锁rDNA复合体中变异性的意义。这个 男性AA表达的适应性意义将被确定 通过实验和实地研究，包括它对 交配制度。我们将确定它们的生活史效应 BB插入比例的数量变化，无论是在 实验室和现场。将使用实地研究来测试 关于BB适应意义的假说。人造的 选拔实验也将用于这一目的，以及 平行实验将在金丝藻中进行，以验证 关于rDNA中选择的差异反应的假设 这两个物种中的多基因家族。

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 yield an integrated life history, and 3) the evolutionary forces that select upon life history traits to determine the aging patterns found in the species. We have been able to study the control of aging at all three levels with the abnormal abdomen (aa) syndrome in Drosophila mercatorum and with the insertion-induced bobbed (bb) syndrome in D. hydei. Both syndromes are caused by insertions that inactivate a large proportion of the 28S ribosomal genes found on the X chromosome. However, the aging effects are modulated by controlling somatic replication of inserted versus noninserted genes in D. mercatorum, whereas quantitative variation in the proportion of inserted genes appears to modulate the syndrome in D. hydei. Both syndromes are associated with a slow-down in larval developmental time, increased early adult fecundity, and decreased adult longevity. These syndromes are adaptive under natural environmental conditions that result in young adult age structures. The genetic architecture of aa will be examined, with the initial focus being on the impact of somatic replication and quantitative variation in insert proportion on the aging phenotypes. Autosomal modifiers will also be isolated and characterized, and it will determined if these modifiers can alter the pattern of pleiotropy. The control of aa expression in males as modulated by the Y chromosome will be investigated, with particular emphasis on the significance of variability in the Y-linked rDNA complex. The adaptive significance of aa expression in males will be determined by experimentation and field studies, including its impact on system of mating. We will determine the life history effects of quantitative variation in insert proportion for bb, both in the laboratory and in the field. Field studies will be used to test hypotheses about the adaptive significance of bb. Artificial selection experiments will also be used for this purpose, and parallel experiments will be done in D. mercatorum in order to test hypotheses about differential response to selection in the rDNA multigene families in these two species.