POPULATION GENETICS OF TRANSPOSABLE ELEMENTS

果蝇Copia样转座因子的群体遗传学研究 将被调查，特别是他们的能力， 物种间的水平转移及其序列范围 相关物种之间的差异。 将追求三个具体目标： 1. 将开发异源转化，以转移 物种间的转座因子 最初，P元件介导的 玫瑰变换系统将D.模拟DNA 来自D.黑腹菌 成功的转型将建立能力 在D基因组以外的基因组中转座。黑腹菌 接下来的实验将确定果蝇物种中 该元件可以被散布并且仍然保持可转座。 在 此外，将研究含P共转化体以确定 无论是杂种发育不全，一种复杂的生殖系异常综合征， 与D中的P元素有关。也发生在其他物种中 其中P被引入。 这些实验将提供 关于转座中宿主元件相互作用的信息，它们将 允许的P-样元素在物种形成的假定作用的评价。 2. D.一个高度不稳定的白色等位基因。将研究毛里求斯 在基因和分子水平上表征插入的DNA 元素 该突变体是令人感兴趣的，因为D. mauritiana和D. simulans 比它们的兄弟物种D具有更少的copia样元素。 黑腹菌 转座因子保留在D.毛里求斯和 D.因此，仿真物可能具有某些不寻常的性质。 这些研究 可以解释为什么一个特定家族的转座因子不分布在 在物种之间，正如从它们的系统发育关系所预期的那样。 在 从长远来看，不稳定的白色等位基因将转化为D。 为了研究它在一个外来物种中的突变特征， 基因组 3. 转座因子copia将在相关物种中进行研究 果蝇，以确定限制图谱变异的程度 在不同物种之间。 限制性酶切图谱的几个不同拷贝 发生在D。melanogaster和copia在D.毛里求斯与 D.黑腹菌 我们的研究将集中在相对收集的菌株 最近 这些研究将揭示协同进化是否发生在 分散重复的多基因家族，这将是重要的， 评估进化力量的相对作用， 这样的元素。

The population genetics of copia-like transposable elements in Drosophila will be investigated, with special reference to their ability to be transferred horizontally among species and their extent of sequence divergence among related species. Three specific aims will be pursued: 1. Heterologous transformation will be developed in order to transfer transposable elements among species. Initially, the P-element-mediated rosy transformation system will be used to transform D. simulans with DNA from D. melanogaster. Successful transformation will establish the ability of P to transpose in genomes other than that of D. melanogaster. Subsequent experiments will determine how widely among Drosophila species this element can be disseminated and still remain transposable. In addition, P-bearing cotransformants will be studied in order to determine whether hybrid dysgenesis, a complex syndrome of germ-line abnormalities associated with P element in D. melanogaster, also occurs in other species into which P has been introduced. These experiments will provide information about host-element interactions in transposition, and they will permit evaluation of the postulated role of P-like elements in speciation. 2. A highly unstable white allele in D. mauritiana will be studied genetically and at the molecular level to characterize an inserted DNA element. This mutant is of interest because D. mauritiana and D. simulans have many fewer copia-like elements than their sibling species D. melanogaster. Transposable elements that are retained in D. mauritiana and D. simulans may therefore have certain unusual properties. These studies may explain why transposable elements of a given family are not distributed among species as would be expected from their phylogenetic affiliation. In the long run the unstable white allele will be transformed into D. melanogaster in order to study its mutational characteristics in an alien genome. 3. The transposable element copia will be studied among related species of Drosophila in order to determine the extent of restriction-map variation within and among species. Several copias differing in restriction map occur in D. melanogaster, and copia in D. mauritiana differs from that in D. melanogaster. Our studies will focus on strains collected relatively recently. These studies will reveal whether concerted evolution occurs in dispersed repeated multigene families, which will be important in evaluating the relative role of the evolutionary forces that impinge upon such elements.