Population Genetics of Transposable Elements

转座因子（te）是在大多数生物体（包括人类）的基因组中存在多个拷贝的DNA序列。它们可以复制自己，从而插入基因组的新位置。有时这些插入引起附近基因的突变，人类遗传疾病中涉及的许多突变都是以这种方式起源的。很明显，至少在某种程度上，TEs的行为就像寄主基因组上的寄生虫，利用寄主作为自己传播的载体。控制宿主基因组中te丰度的力量是一个需要继续研究的问题。理解这些力量对于我们了解塑造基因组组织的因素和突变的起源是很重要的。果蝇是研究这些问题的一个有用的模式生物。TEs的特性在果蝇和其他生物（如人类）中是相似的；在果蝇中，较短的生成时间和易于研究的特性使得遗传问题比在大型生物中更有效地得到解决。拟议的研究继续对果蝇TEs的种群水平特性进行调查。一个主要目标是获得果蝇te在基因组中移动速率的更精确估计；这一信息对于解释之前关于te在个体间分布的研究至关重要。第二个目标是检查所有被研究个体基因组中插入特定位点的te。这些病例是例外，因为TE插入的不良影响通常意味着TE插入仅在给定位置的低频率处被发现。

9527717 CHARLESWORTH Transposable elements (TEs) are DNA sequences that are present in multiple copies in the genomes of most organisms, including humans. They can make new copies of themselves, which can insert into new places in the genome. Sometimes these insertions cause mutations of nearby genes, and a number of mutations involved in human genetic diseases have originated this way. It seems clear that TEs behave, at least in part, as parasites on the genomes of their hosts, using them as a vehicle for their own transmission. The forces responsible for controlling the abundances of TEs in the genomes of their hosts are a matter for continuing research. Understanding these forces is important for our knowledge of the factors that shape the organization of the genome, and for the origin of mutations. The fruitfly Drosophila is a useful model organism for research into these questions. The properties of TEs are similar in Drosophila and other organisms such as humans; in Drosophila the short generation time and ease of study allow genetic questions to be addressed much more efficiently than in larger organisms. The proposed research continues an investigation of the population-level properties of Drosophila TEs. A major objective is to obtain more precise estimates of the rates at which Drosophila TEs move around the genome; this information is vital for interpreting previous studies of the distribution of TEs between individuals. A second objective is to examine TEs that are inserted at a particular site in the genome in all studied individuals. These cases are exceptional, as the adverse effects of TE insertions usually mean that TE insertions are found only at low frequencies at a given location.