Biology Reference
In-Depth Information
Past experience with natural enemies genetically manipulated by traditional
selection methods suggests that the most readily implemented pest-management
projects using GM natural enemies will be those where releases can be conducted
in relatively small areas such as temporary cropping systems, or where the natural
enemy has a low dispersal rate and can be established in individual orchards, or
where the natural enemy is released into a geographic region where the wild strain
does not occur. The most difficult projects to implement are likely to be those in
which the transgenic strain is expected to replace the endemic population. Projects
that require the GM strain to replace a wild strain may require very strong selection
or “drivers.” Teams of experts may have to develop the mass-rearing technology,
quality-control methods, and the necessary information on population structure
and hidden partial reproductive isolation mechanisms that are likely to occur.
Other questions remain. For example, is informed consent of humans in the
release zone required before GM mosquitoes are released that are unable to
transmit human diseases? Who bears the burden of liability should environmen-
tal, or other, harm occurs after releasing GMAs? Scientists working for nonprofit
organizations, such as universities and governmental agencies, are developing
most transgenic arthropods. Will the commercial development and sale of trans-
genic arthropods create new ethical or legal issues?
Significant and rapid advances have been achieved in GM of arthropods
and the identification of potentially useful genes to insert. New opportunities
should arise over the next few years to identify useful genes now that more
arthropod genome projects have been completed (see Chapter 7).
There remains controversy as to the role that transgenic mosquitoes could
play in controlling or eradicating diseases such as malaria (
Marshall et al. 2010
).
Curtis (2000)
presents one view:
“There is much excitement about transgenesis as a way to generate strains of
mosquito that cannot transmit malaria. If a single dominant gene with these
properties could be engineered, this would be an improvement on
Plasmodium
nonsusceptible strains that have already been selected by old-fashioned
breeding techniques. However, without extremely reliable systems for driving
the transgenes into wild vector populations, possession of a nontransmitter
strain would be of no practical use. Even if a totally reliable gene-driving system
were produced, there might well be strong political objections to the irrevocable
release of genetically manipulated insects that bite people.”
Deploying any GMA in a pest-management program is an awesome challenge,
requiring risk assessments, detailed knowledge of the population genetics, biology,
and behavior of the target species under field conditions, as well as coordinated
