A female pea aphid giving birth to live young.

Aphids teach scientists a thing or two

Reference: 10/21

In recently unravelling the genome of the pea aphid, an international consortium of researchers has taken a major step towards understanding how to better control that bane of farmers and gardeners around the world.

• 9 March 2010

Consortium member, Dr Owain Edwards, (CRC for National Plant Biosecurity and CSIRO Entomology), is leading a team of CSIRO colleagues in research designed to reveal which genes control what function in the aphid.

“Because of their complex life style, aphids can provide valuable insights into how information in the genome is passed from generation to generation without any change in the genome’s basic building blocks,” Dr Edwards said.

“This sort of “epigenetic” information (where changes in an organism happen without changes in its DNA) is now known to be important in controlling diseases such as cancer and diabetes.”

While aphids seem simple, they lead complicated lives producing sexual egg laying and asexual live-bearing females and wingless and winged forms – all from the same genetic code.

In fact, the pea aphid is able to produce seven different forms from the same genome in response to environmental cues such as temperature, day length or nutrition.

Epigenetics provides an ‘environmental’ memory. The environment experienced by a mother can cause genes to be turned on or off in her offspring, like the mute button on a television. 

“For example, in one aphid species, resistance to insecticides at birth is determined by whether the mother or grandmother was exposed to these insecticides during her lifetime,” Dr Edwards said.

“Stem cells are important because they do not yet have an epigenetic code. This is ‘reset’ when eggs are produced. Aphids may therefore provide clues to producing stem cells, as they are one of few animals that can reset this epigenetic code without producing eggs.

Other work the scientists were involved in included research on genes that allow aphids to feed on plants, including genes in the salivary gland, and genes that help the aphid to break down plant toxins.

The results were recently published in the prestigious online journal PLoS Biology.

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