James Meek, science correspondent The Guardian
Scientists
are preparing to start trials of the world's first genetically
modified insect, an unnatural born killer moth that will fly over
cotton fields, passing a deadly gene on to its pestilent kin as
an alternative to pesticide.
Although the
GM moth will be released in Arizona, the technology used to create
the killer gene has been developed by a British team led by Luke
Alphey, of Oxford University. The scientists believe that the
chances of the killer gene spreading beyond the species it is
intended to harm, the pink bollworm, is very small, and would
do no harm if it did.
But the US
department of agriculture still has to give consent for the first
part of the trial, which would involve a tightly controlled release
of moths with another gene inserted to track any possible cross-species
transfer.
Scientists
need to target the bollworm larvae, which feed on cotton plants,
before developing into moths. The idea is to take insect eggs
in the lab and insert into their DNA a gene from a fruit fly which
would normally damage their metabolism so badly that they would
die.
In the lab,
however, the larvae survive, because they are dosed with an antidote
to the effects of the killer gene. They will grow into adult moths,
which are naturally immune to the effects of the gene, and will
then be released over the cotton fields in huge numbers.
Unaware that
by mating they are both creating and assassinating the next generation,
the GM moths will mate with wild moths and each other. The female
moths will lay their eggs as normal. But their offspring will
have inherited the killer gene. In the wild, the larvae will find
no antidote and will die.
In the initial
trial, which could take place next year, 3,600 moths will be given
a jellyfish gene that glows under special light instead of the
killer gene. This will show what happens to GM insects when they
encounter their wild counterparts and other species.
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