Population Genetics of Transposable Elements

最近遗传学的一个令人兴奋的发现是， 发现从细菌到人类的生物体的基因组 含有DNA序列家族， 可以插入基因组其他地方的新拷贝。 这些被称为转座因子（TE）。 的插入 进入或靠近基因的TE可能会导致具有有害生物的突变。 影响个体的生存能力或生育能力。 例如，在人类中，TE插入已经涉及 导致血友病和乳腺癌的突变。 的发现 TEs引发了一场关于控制力性质的辩论 TE在其宿主物种种群内的分布。 先前对果蝇、酵母和细菌的研究表明， 虽然同一个TE家族的成员有几个拷贝， 可能存在于宿主个体的基因组中， 每个人可以具有不同数量的副本。 此外，委员会认为， 这些通常被插入到不同的位置 在不同的宿主个体中，这表明 部队阻止TE填满所有的站点 在基因组中占有一席之地。 本研究旨在帮助确定 这些部队进一步的数据分布的TE的内 果蝇种群将被收集并与 理论模型的预测。 这将提供检查 上述意见的一般性。 此外，本发明还提供了一种方法， 将测试TE的趋势，积累在 基因重组受到限制的基因组区域。 这种趋势是由遗传学假说预测的， 位于不同位置的同源TE之间的交换 可以产生染色体损伤，消除相关的TE， 从而防止它们的传播。 其中一个地区是已知的 中心异染色质。 该地区以前没有 由于技术上的困难， 与高重复DNA序列的丰度相关， 这一区域 DNA技术的最新进展意味着， 现在可以研究异染色质中的TE丰度， 这是该项目的一个重点。

An exciting recent finding of genetics has been the discovery that the genomes of organisms from bacteria to humans contain families of DNA sequences that have the ability to make new copies of themselves that can insert elsewhere in the genome. These are known as transposable elements (TEs). The insertion of a TE into or near a gene may cause a mutation with a harmful effect on the survival ability or fertility of the individual. For example, in humans TE insertions have been implicated in mutations causing hemophilia and breast cancer. The discovery of TEs has led to a debate on the nature of the forces that control the distribution of TEs within populations of their host species. Previous studies in Drosophila, yeast and bacteria have shown that, although several copies of members of the same family of TE may be present within a host individual's genome, different individuals may have different numbers of copies. Furthermore, these are generally found to be inserted into different places in different host individuals, suggesting that some force of forces are preventing TE's from filling up all the sites available for occupation within the genome. The present study is designed to help identify the nature of these forces Further data on the distribution of TE's within a population of Drosophila will be collected and compared with the predictions of theoretical models. This will provide a check of the generality of the observations mentioned above. In addition, tests will be made of the tendency of TEs to accumulate in regions of the genome where genetic recombination is restricted. Such a tendency is predicted by the hypothesis that genetic exchange between homologous TE's located in different locations can produce chromosomal damage that eliminates the TEs concerned, and hence acts to prevent their spread. One such region is known as the centric heterochromatin. This region has not previously been studied in detail because of technical difficulties associated with the abundance of highly repeated DNA sequences in this region. Recent advances in DNA technology mean that it is now possible to study TE abundance in the heterochromatin, and this forms a major focus of the project.