Dissertation Research: Phylogenetic Analysis of the Drosophila Montium Subgroup: Horizontal and Vertical Transmission of Mobile Elements

9423508西蒙斯这项研究将研究一组果蝇身上一种名为hobo的跳跃基因的进化。跳跃基因是遗传序列的一部分，它们在生物体(宿主)的基因组中独立发挥作用。跳跃基因会自己沿着染色体移动。由于它们的流动性，流浪汉元素已被认为会不利地改变其宿主内基因的功能。跳跃基因被发现大量存在于包括人类在内的各种生物体中。因为跳跃基因的运动和功能独立于其他基因，它们并不总是以通常的方式从父母传给后代，代代相传。相反，跳跃基因可以跨物种传播，甚至是远亲(例如，从植物到动物)，就像一种疾病。这种传染方式被称为水平传播。跳跃基因已知会感染远亲果蝇的染色体，这使果蝇成为检测跳跃基因效应的良好模式系统。然而，为了确定跳跃基因的遗传模式，必须首先知道寄主物种的关系(分类学)。这个项目的第一个目标将是建立果蝇亚群中与黑腹果蝇密切相关的果蝇物种之间的关系。为了了解包括人类在内的所有真核生物中基因的功能，黑腹果蝇一直是一种被广泛研究的生物。然而，相比之下，这类果蝇的分类相对鲜为人知。研究人员将利用这些果蝇的一些形态特征和它们的基因DNA序列来确定这些果蝇的分类。一旦果蝇分类建立，流浪分子的存在或不存在就可以与分类学联系起来，从而推断流浪分子的进化史。

9423508 SIMMONS This study will examine the evolution of a jumping gene, called hobo in a group of fruit flies. Jumping genes are portions of the genetic sequence which function independently within an organism's (host's) genome. Jumping genes move along chromosomes on their own. Due to their mobility, hobo elements have been known to unfavorably alter the functioning of genes within their host. Jumping genes are found to be present in substantial numbers across a wide variety of organisms, including humans. Because jumping genes move and function independently of other genes they are not always inherited in the usual manner from parent to offspring across generations. Instead jumping genes can be transmitted across species, even distantly related ones (e.g., from plants to animals) like a disease. This infectious mode is termed horizontal transmission. Jumping genes have been known to infect the chromosomes of distantly related species of fruit flies, which makes the flies a good model system for examing effects of jumping genes. However, in order to determine the inheritance pattern for a jumping gene one must first know the relationships (taxonomy) of the host species. This project's first goal will be to establish the relationships between species of fruit flies of the Drosophlia montium subgroup which are closely related to Drosophlila melanogaster. Drosophila melanogaster has been an organism intensively studied in order to understand the function of genes in all eukaryotes, including humans. Yet, in contrast, the taxonomy of this group of drosophilids is relatively unknown. The investigators will determine the taxonomy of these fruit fly species by using some features of their morphology and the DNA sequences of their genes. Once the fruit fly taxonomy is established, the presence or absence of the hobo element can be related to the taxonomy in order to infer the evolutionary history of the hobo elements.