The TE team, lead by the Tu laboratory, uncovered and described more than 1,000 transposable elements, which occupy approximately 50 percent of the entire Ae. aegypti genome. For example, a transposable element named Feilai has more than 50,000 copies interspersed in the genome. By comparison, Anopheles gambiae, the malaria mosquito genome is probably less than 25 percent TEs. The Ae. aegypti genome is five times the size of the malaria mosquito genome.
"Although the majority of protein coding TE copies in Ae. aegypti appear to be degenerate, a significant number of elements have potentially active TE copies, indicating that they may be developed as tools for genetic studies of mosquitoes," Tu said.
"If you look at the genome as an ecological system, TEs are different lineages that co-evolve with the rest of the genome" said Tu. "They evolve different relationships with the genome. Some are genetic parasites; they appear to do nothing except replicate within the genome. Others are used by the host -- the individual organism's genetic machinery --to perform biological functions."
TEs may be developed as genetic tools to study the interaction between mosquitoes and pathogens, and thus may lead to controls of transmission of disease, Tu said. Control might take the form of a genetic control, such as using TEs to carry a gene into the genome that would make the mosquito resistant to the virus and stop its role as a vector for disease. Although that scenario is challenging, the payoff is potentially great, Tu said.
"By introducing TEs in a more or less random way to see what happens to the laboratory mosquitoes, the TEs become a tool to s