Genetic Modification of Pest and Beneficial Insects for Pest-Management Programs - Insect Molecular Genetics - page 680

14.11.2 Relative Risks
The least risky genetically modified arthropods could be the domesticated silk-
moth ( B. mori ), which is unable to survive on its own in the wild. Transgenic silk
moths are able to produce both improved silk and proteins for pharmaceutical
use ( Zhao et al. 2010, Tatematsu et al. 2010 ). Transgenic B. mori are unlikely to
have a negative effect on the environment because they should not be able to
persist if they were accidentally released.
Transgenic pest or beneficial arthropods that are sterile and unable to repro-
duce should pose a lower risk than strains that are able to reproduce and persist
in the environment. Transgenic pest or beneficial arthropods that are unable to
persist because the environment is unsuitable during a portion of the year also
could pose a low risk ( McDermott and Hoy 1997 , Hoy 2000a,b ). Honey bees are
only semidomesticated and thus can escape human management to survive in
the wild, so transgenic honey bees could pose a greater environmental risk than
the domesticated silk moth for this reason.
14.11.3 General Risk Issues
Evaluating potential risks associated with releasing GMAs will likely include,
as a minimum, the questions or principles outlined in Tables 14.2 and 14.7 , but
other issues may become important as we learn more about risk-assessment pro-
cedures ( Foster et al. 2000, Kapuscinski 2002, Marrelli et al. 2006, 2007, Franz
2009 ). Current concerns can be summarized as follows:
l Is the genetically modified population stable under a variety of
environmental conditions?
l Has its host or prey range been altered?
l Does it have the potential to persist in the environment?
l Will the modified strain will have unintended effects on other species or
environmental processes?
l In the case of vector insects, will they cause harm to humans?
The first three questions are relatively easy to answer with a variety of labora-
tory experiments. The fourth issue is much more difficult to answer. Releases of
GMAs in the United States are now evaluated by several regulatory agencies on
a case-by-case basis. Permits are issued at present only for short-term releases
in controlled situations so that unexpected outcomes might be mitigated more
readily ( Young et al. 2000 ).
14.11.4 Horizontal Transfer (HT)
One risk issue that is especially difficult to quantify is the risk of horizontal trans-
fer (HT) of transgenes, TEs, or Wolbachia to other organisms ( Droge et al. 1998 ).