McClintock and the Ac/Ds Transposable Elements of Corn

Yeast TY Elements

Drosophila Transposable Elements

Drosophila P Elements

Bacterial Transposable Elements

Study Questions

Transposable Genetic Elements WWW Links

Genetic Topics

Drosophila Transposable Elements

The analysis of transposable elements in Drosophila has been quite extensive. As much as 15% of the genome of this species is mobile genetic DNA. As many as 30 classes of transposons have been found, and many of these are retrotransposons. Furthermore, the number of members of any one family varies between different Drosophila strains. As with other retrotransposons, they contain LTRs at each end, and DNA at the insertion site is duplicated. One feature that discriminates the classes is the size of the duplication. Members of copia class generate 5-bp, duplications whereas gypsy elements create 4-bp duplications. For both classes, the duplications are direct repeats. After extensive molecular analysis, it has been determined that many of the classical Drosophila mutations are the result of transposon insertion. Interestingly, insertion does not always eliminate the function of the gene product, but rather changes its function enough to result in another phenotype.

Copyright © 1997. Phillip McClean