Significance Telomeres are essential nuclear organelles whose functional integrity is linked to proliferation control. Every eukaryotic organism must compensate for terminal loss of DNA from chromosome ends, because DNA polymerases cannot completely replicate the ends of linear chromosomes. So far, evidence for two different terminal elongation mechanisms has been established.
Most eukaryotes have a short, tandemly repeated DNA sequence motif on their chromosome ends.
These telomeric tandem arrays are extended by telomerase, a specific reverse transcriptase. However, elongation by telomerase appears not to be universal, because our work in the past years has provided evidence for a very different telomere elongation mechanism in the dipteran fly Drosophila melanogaster that is based on terminal attachment of specific retrotransposable elements. Such telomerase-independent elongation mechanisms are now being discovered in experiments that are aimed at inhibiting or eliminating telomerase activity as a mean of proliferation control in tumors. I am studying the structure and function of telomeres in Drosophila melanogaster and in the malaria transmitting the mosquito Anopheles gambiae . Information gained from studies on telomeres in mosquitoes may lead to a new approach to germ line transformation and eventually may become useful in controlling the transmission of the malaria parasite.