Biology Reference
In-Depth Information
populations by a GMA, will require permanent establishment of the GMA in the
environment and may require the use of “drive” mechanisms. Several drive mech-
anisms, such as release of active TEs, Medea , or Wolbachia strains that cause cyto-
plasmic incompatibility, have been proposed as drive elements.
14.2 Introduction
This chapter provides an overview of the progress in developing genetically
modified arthropods (GMAs) for use in pest-management programs or for pro-
ducing products for use by humans (silk, drugs, honey, pollination services).
Enormous efforts have been made in the past few years to develop and test
GMAs, especially genetically modified mosquitoes. The use of RNAi is being eval-
uated as a method of controlling pest arthropods, and mosquitoes containing
Wolbachia isolated from another insect species have been tested in the field.
Because the area of research is diverse and is expanding rapidly, it is difficult
to include all relevant citations. However, key references provide the reader an
entry to the literature and Table 14.1 lists some of the diverse research projects
being conducted involving GMAs.
14.3 Why Genetically Modify Insects?
14.3.1 Beneficial Insects
Domesticated and semidomesticated insects have been modified by traditional
breeding methods for hundreds of years. Artificial selection has improved
disease resistance and silk production in Bombyx mori ( Yokoyama 1979,
Gopinathan 1992 ) and disease resistance and pollination attributes in Apis
mellifera ( Rothenbuhler 1979 ).
The genetic modification of silk moths to produce improved silk or to produce
proteins used in drugs is an active area of research ( Goldsmith et al. 2005, Royer
et al. 2005, Tatematsu et al. 2010, Zhao et al. 2010 ). Teule et al. (2012) noted that
silk fibers are used as sutures, and could be used for wound dressings, artificial
ligaments, tendons, and other applications in human medicine. Spiders produce
silk of superior mechanical properties compared to the silk produced by B. mori ,
but spiders cannot be mass reared as efficiently. Silk-protein genes were cloned
from a spider and a chimeric B. mori -spider silk gene was developed and inserted
into silk moths with a piggyBac vector ( Teule et  al. 2012 ). The composite silk
fibers produced by the transgenic silk moth had improved mechanical properties
and the silk was produced in the same place and at the same time as native silk
proteins due to the use of an appropriate promoter. Grenier et al. (2004) devel-
oped new B. mori strains to reduce risk and improve the stability of transgenic
lines by producing lines that reproduced by parthenogenesis (to reduce loss or
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