Maternally-inherited gene mutations help NZ scientists in pest control

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A new gene technology, which can help eradicate pests like mice and wasps one day, has yielded positive results on fruit flies in lab tests, a new study has revealed.

Neil Gemmell, head of University of Otago's Department of Anatomy, said the "Trojan Female Technique," in which females pass on genes that make male offspring infertile, offers pest-control advantages that are likely to help New Zealand to reach the goal of "Predator Free 2050".

The "Predator Free 2050" is a plan put forth by the New Zealand government to eradicate the most damaging introduced predators that threaten the country's nature, economy and primary sector.

Brushtail possums, protected in their native Australia, have become reviled ‍feral pests in New Zealand. /VCG Photo

In a research paper published by eLife on Friday, Gemmell and co-authors reported their success in turning their theory about Trojan female fruit flies into reality in the lab.

"This is a world-first proof-of-concept and we need to test the general applicability of this approach more widely," Gemmell said, adding that the technique uses naturally occurring mutations in mitochondrial DNA that affect male, but not female, fertility and fitness.

Mitochondria are considered the "power generators" of a cell and turn oxygen and nutrients into chemical energy which runs the cell's metabolic activities. "The essence of our idea is to use these mitochondrial mutations to produce continuous, self-sustaining biological control," he said.

"What we discovered some years back is that, as a by-product of the maternal inheritance of mitochondrial DNA, mutations that affect only males can occur quite commonly in populations, potentially contributing to fertility issues in some populations," he added.

"Our idea turns this problem around. If these mutations can affect population viability, we wondered if they might be turned into a tool that has the potential to control and even eradicate pests," Gemmell said.

Farmland on the banks of Lake Hawea, Central Otago, South Island, New Zealand. /VCG Photo

Their study showed that population reduction, albeit at this stage quite modest, can be achieved in laboratory-raised fruit flies, and broadening this technique to introduce Trojan females into wasp and pasture weevil populations is under way.

While there are many tools to control pest populations, this might be an important part of a growing arsenal, and around New Zealand there is a great deal of interest in this approach as a way to control rats, possums and stoats as part of the "Predator Free 2050" goal, Gemmell pointed out.

Pests set New Zealand back about 3.3 billion NZ dollars (2.4 billion US dollars) a year through lost productivity and cause profound damage to native fauna and flora. "The implications globally are even larger, particularly when insect-borne diseases, like malaria, are considered," he said.

(Source: Xinhua)