Genetic Dissection: Imprinting Drosophila melanogaster

染色体保留了其起源的记忆，无论是父系的还是母系的。这些信息以序列独立的方式编码，因为相同的序列在不同的生物体中可能表现不同。这个标记在生物体的整个体细胞中是稳定的，只有在传递给后代之前才会被重置。对这种印记的解释可能会影响染色体的调节方式——它是否在发育过程中丢失，或者相关基因的表达是否被调节或抑制。这种现象导致了哺乳动物中不寻常的单系遗传疾病。不能保持这种印记也与晚发性疾病有关，比如威尔姆斯瘤。为了研究印迹的要求和调控，我将使用最近在果蝇身上发现的一个印迹的例子。首先，我将筛选基因组中影响印记建立、维持和解释能力的突变。通过利用跨越大部分基因组的缺陷。我就能发现与剂量有关的印记修饰剂。其次，我将描述在P元素的y链接插入上发生印迹起始的要求。使用一组这样的插入，我将确定成为印迹的插入之间的相似性，并尝试绘制建立印迹所需的序列或染色体结构要求。

Chromosomes retain memory of their origin, whether paternal or maternal. Such information is coded in a sequence-independent fashion, as identical sequences may behave differently in different organisms. The marking is stable throughout the soma of an organism, only to be reset prior to transmission to progeny. The interpretation of this imprint may affect how a chromosome is regulated - whether it is lost in development, or whether expression of linked genes is modulated or repressed. This phenomenon leads to the unusual case of uniparentally- inherited disorders in mammals. The failure to maintain this imprint has also been linked with later-onset diseases, such as Wilms' Tumors. I will use a recently-characterized example of imprinting in Drosophila in order to study the requirements for, and regulation of, imprinting. First, I will screen for mutations in the genome that affect the ability for an imprint to be set, maintained, and interpreted. By using deficiencies that span most of the genome. I will be able to uncover dose-dependent modifiers of imprinting. Second, I will characterize the requirements for the initiation of imprinting to occur on a Y-linked insertion of a P- element. Using a set of such inserts, I will determine the similarities between inserts that become imprinted, and attempt to map sequence or chromosome structure requirements necessary for imprinting to become established.