Molecular Evolution of hobo Transposable Elements in Drosophila

9318823西蒙斯转座因子（TE）是在所有生物体中发现的基因序列，当它们从一个染色体位点移动到另一个染色体位点时，它们可以引起各种各样的有害影响。TE可以从父母传给后代（垂直），也可以从一个宿主物种传给另一个宿主物种（横向），因此它们的行为类似于寄生虫。西蒙斯博士对确定这种横向转移到流浪汉（果蝇属昆虫中的一种转座因子）的模式和相对频率感兴趣。她之前发表的研究表明，活跃的流浪汉元素在最近的过去已经在果蝇的四个物种之间横向转移。然而，最近的研究表明，其他果蝇物种的流浪汉序列可能是垂直传播的。西蒙斯博士将通过克隆和DNA测序来自几个物种果蝇的该元件的全长拷贝，对果蝇中流浪汉的横向与垂直传播进行更全面的分析。这些序列将用于构建这些物种中流浪汉元件的“家谱”，并将所得的家谱与为宿主物种构建的家谱进行比较。两棵树形态相同的地方表明流浪汉是垂直传播的物种，而两棵树不一致的地方表明可能发生横向传播事件。这些研究将成为理解各种生物体中横向遗传转移事件机制频率的基础。

9318823 Simmons Transposable elements (TEs) are genetic sequences found in all organisms that can cause a wide variety of deleterious effects when they move from one chromosomal site to another. TEs can be transmitted both from parent to offspring (vertically) and from one host species to another (laterally), so that their behavior resembles that of a parasite. Dr. Simmons is interested in determining the pattern and relative frequency of such lateral transfer events to hobo, a transposable element in the insect genus Drosophila. Her previous published work showed that active hobo elements have been laterally transferred among four species within the Drosophila in the recent past. Recent work indicates, however, that hobo sequences in other Drosophila species may have been vertically transmitted. Dr. Simmons will perform a more complete analysis of lateral vs. vertical transmission of hobo in Drosophila by cloning and DNA-sequencing full-length copies of the element from several species Drosophila. The sequences will be used to construct a "family tree" for the hobo element in these species, and the resulting tree will be compared to a tree to be constructed for the host species. Places where the two trees have the same form will indicate species in which hobo has been vertically transmitted, while places where the two trees are not congruent indicate potential lateral transfer events. These studies will form the backbone of the efforts to understand the frequency of the mechanisms of lateral genetic transfer events occurring in all sorts of organisms.