Molecular Population Genetics of Transposable Elements in Drosophila

点击翻译按钮获取中文摘要

Transposable elements or TEs, which as examples of so- called "selfish DNA" function to ensure their own survival and reproduction, exist (in multiple copies) in the chromosomes of all organisms, often causing mutations. A portion of the TE's own genome is devoted to directing its own reproduction independently of the host's genes, thereby enabling it to spread through a host organism's chromosomes quickly, even if the TE has a slightly detrimental effect. Drosophila melanogaster, the fruit fly, is known to have a large number of different kinds of transposable elements. When one such element, called hobo, moves among chromosomes, it causes hybrid dysgenesis, which leads to sterility, high mutation rates, chromosome breaks, and other deleterious effects, so its persistence over millennia of evolution is quite puzzling. By comparing DNA sequences of hobo elements in different populations and in other closely related Drosophila species (D. simulans for example), it will be possible to learn about the rate at which hobo elements have evolved, what selective forces have acted to modify genetic function, and mode of TE transmission between species. In the long run, studies of this type are expected to yield a fundamental understanding of how organisms have dealt with "DNA parasites" over time, as well as how the action of TEs, via mutation, have led to useful, novel gene functions.