Insect Control: Biological and Synthetic Agents - Index of

12 Insect Transformation for Use in Control
P W Atkinson, University of California, Riverside,
CA, USA
D A O’Brochta, University of Maryland
Biotechnology Institute, College Park, MD, USA
A S Robinson, FAO/IAEA Agriculture and
Biotechnology Laboratory, Seibersdorf, Austria
ß 2010, 2005 Elsevier B.V. All Rights Reserved
12.1. Introduction 439
12.2. The Status of Transgenic-Based Insect Control Programs 441
12.2.1. Load Imposition on the Target Population 441
12.2.2. Challenges of Long-Term Gene Introduction into Natural Populations 442
12.2.3. Engineering of Beneficial Insects 444
12.3. Conclusion 444
12.1. Introduction
In the previous series of Comprehensive Insect
Physiology, Biochemistry, and Pharmacology, the
corresponding article by Whitten (1985) dealing,
briefly, with insect transformation technology raised
two points about the problems that the extension
of this technology into the field would most likely
face. The prescience of these forecasts is even more
remarkable given that it was written shortly after the
development of a genetic transformation technology
for Drosophila melanogaster and so was authored
some 10 years before the repeatable transposable
element-mediated transformation of nondrosophilid
pest insect species.
In writing this review we have chosen not to regurgitate
information already presented in recent reviews
on the subject (Robinson and Franz, 2000; Atkinson,
2002; Handler, 2002; Robinson, 2002; Wimmer,
2003; Robinson et al., 2004), and we will not discuss
the issue of the development of a regulatory framework
for the use of this technology. Two recent
reports on the regulation of the release of transgenic
arthropods have recently been published and the
reader is referred to these for illumination as to
the state of this issue (National Research Council,
2002; Pew Initiative on Food and Biotechnology,
2004). It would also be difficult to improve on
Whitten’s (1985) review, which comprehensively
examined the history, conceptual basis, and application
of genetic control in insects. Rather, under
examination are two points raised by Whitten as a
means to assess critically the current status of the
application of genetically engineered insects to help
solve problems in medicine and agriculture.
It must first be said that, some 20 years after the
publication of Whitten’s review, there is not one
single example of the use of genetically engineered
pest insects in the field. This is despite the first
report of the transformation of an anopheline mosquito
by Miller et al. (1987), and then, 8 years later,
the first of several published reports ultimately
describing five new transposable elements used to
transform a range of nondrosophilid insect species,
e.g., the Mediterranean fruit fly, Ceratitis capitata,
and the yellow fever mosquito, Aedes aegypti
(review: Robinson et al., 2004).
In his 1985 review, Whitten stated:
Clearly it is unlikely that our technical ability to transform
a species will prove lacking: rather, it is our
uncertainty concerning what genetic modifications
are desirable that will usually prove to be the major
impediment.
The current state of the field supports this prediction.
Repeatable genetic transformation technologies
for nondrosophilid insects have now existed
for 9 years. While the development of these did
prove to be more problematic than expected and
awaited the discovery of new transposable elements
such as Minos (Franz et al., 1994), Mos1 (Medhora
et al., 1991), piggyBac (Cary et al., 1989), and
Hermes (Warren et al., 1994), the application of
these technologies to practical problems in medical,
veterinary, and economic entomology has not
occurred. Several reasons exist for this, the most
important one being the difficulty in discovering
genetic and biochemical systems that might prove
to be effective genetic control strategies in the field.
Even as recently as 2001, the most elegant examples
of using genetic-based strategies to selectively eliminate
females (e.g., for the augmentation of a sterile
insect technology) occurred in D. melanogaster and
with experimental population sizes several orders