The genetic mapping of a tiny, venomous parasitic wasp could lead to chemical-free pest control and provide insights into how the environment contributes to human disease.

The claim is made by a group of 157 scientists from around the world, who took four years to sequence the genetic map of three species of the Nasonia wasp.

They also say the sequencing shows Nasonia has potential to become a model genetic system for understanding evolutionary and developmental genetics.

In today's Science journal, the team, including Australian researchers, show some of the key genes involved in making the wasp such an effective killer.

Parasitoids such as the Nasonia wasp inject venom into their prey, then lay eggs on or inside the host, which is then eaten and eventually killed by the developing young.

Pest control

"There are over 600,000 species of these amazing critters, and we owe them a lot. If it weren't for parasitoids and other natural enemies, we would be knee-deep in pest insects," says Nasonia Genome Working Group team leader Professor John Werren, of the University of Rochester in New York.

Parasitoid wasps are like "smart bombs" that seek out and kill only specific kinds of insects, says Werren.

"Therefore, if we can harness their full potential, they would be vastly preferable to chemical pesticides, which broadly kill or poison many organisms in the environment, including us."

Professor Ryszard Maleszka of the Research School of Biology at the Australian National University, says the research is likely to be used to develop non-chemical pest controls.

Changing gene behaviour

Maleszka's team looked at the genes involved in DNA methylation, or how gene behaviour is changed by environmental factors.

He says in honey bees DNA methylation tells the genes whether to produce a highly fertile queen or a sterile worker, based on nutrition.

In the Nasonia wasp, Maleszka believes methylation is used more for controlling development and deciding how development should proceed, but he says more analysis needs to be done following the sequencing.

He says understanding the interaction between environment and genes, known as epigenetics, is important in understanding human diseases.

"By understanding more about how methylation works in a relatively simple creature like Nasonia wasps, we can learn more about how it works in humans, where the process is turning out to be important in a range of conditions such as cancer, obesity and mental illness," says Maleszka.

His laboratory also looked at the gene family known as 'yellow-like' or 'major royal jelly' proteins, which play a role in immunity and development. In honey bees they also determine the caste.

Maleszka says the Nasonia genome has 26 of these genes, the largest number yet known in an insect population.