People tend to fall into camps in these discussions. There are those who are suspicious of genetic tinkering of any sort and there are those who think that genetic modification is harmless and a boon to mankind. No doubt the truth lies somewhere in between. 

When you use RNA to target cell processes, the outcome is what we are concerned about. The RNA itself is as innocuous as table salt. However, if it gets inside the cell and is not treated as a foreign object, it can bring about radical alterations in cell processes. 

Sort of like a few lines of computer code. If the code never gets into the right place, it simply remains code. But if it makes its way into your operating system and is malicious code, it can shut down your whole machine. Or worse, it sits in there silently copying itself and sending the bug to all your friends via email. If you or I saw the code we wouldn't know whether it was a virus, a love letter or gobbledygook. 

I have posed questions and have been greeted with silence or with oblique comments like "nothing is 100% certain." If we are to trust the scientists who intend to implement these techniques, it falls on them to gain our trust by being open and addressing our concerns in a responsive -- not dismissive way. 

* * *

Major concerns regarding the use of RNAi in insect pest control include the
specificity of action and off-target effects (Auer and Frederick 2009). Comparative
studies have established a correlation between the degree of identity between
dsRNA and target gene and the degree of silencing (Baum et al. 2007). 

Thus, the specificity of the RNAi effect, whether it targets a single species or a group of species
of a wider taxonomic group, could be achieved by careful selection of the dsRNA
that is produced: unique sequences may target efficiently only a single species while
more conserved sequences could achieve more broad specificity (Runo et al. 2011).

Emergence of resistance is always a major issue when new control strategies for
insect pests are developed.  It is not known for insect species that are sensitive to RNAi at what
frequency individuals exist in natural populations that are more resistant to RNAi.
Under selection pressure, such resistant alleles could spread rapidly through the
population and render deficient the RNAi approach for pest control.

It is evident that the modern technology of second-generation
sequencing will also significantly contribute forming a key in the success for the
RNAi approach. So far several have been analyzed; good examples [include]
the exotic invasive insect pest emerald ash borer Agrilus planipennis (Mittapalli et al. 2010). 

In the latter studies, it was of interest that the
authors were able to broaden the target selection for RNAi from just insect midgutspecific
genes to targets in the whole insect body. We believe these tools will help
to identify new sensitive insecticide targets for designing RNAi-based technology
against insect damage.

G. Smagghe and I. Diaz, eds. (2012) Arthropod-Plant Interactions: Novel Insights and Approaches for IPM, Progress in Biological Control 14

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