Biology Reference
In-Depth Information
Molecular methods could allow unique markers, such as red or green fluo-
rescent protein, to be inserted into sterile insects, which would allow SIRM
program managers to more easily discriminate between released sterile males
and wild fertile males caught in the traps used to monitor the progress of the
SIRM program (
Handler and McCombs 2000, Higgs and Lewis 2000
,
Handler and
Harrell 2001
). Marking methods using fluorescent dusts or dyes are not satisfac-
tory because they can reduce fitness of the insects and the dusts/dyes do not
always persist, which could lead program managers to conclude that more wild
insects are present in the field than is true.
Other significant benefits could be obtained if molecular-genetic methods
make it possible to control the sex of insects being reared in SIRM programs, to
introduce lethal genes or genetic loads into pest populations, or to produce vec-
tors of human and animal diseases that are unable to transmit diseases such as
malaria, dengue, yellow fever, and sleeping sickness.
Molecular-genetic techniques could make genetic improvement of beneficial
insects, such as silk moths, honey bees, or natural enemies more efficient and
less expensive (
Beckendorf and Hoy 1985
,
Walker 1989
,
Hoy 1990a,b, Heilmann
et al. 1994, Beckage 1998
). Once a useful gene has been cloned, it could be
inserted into many beneficial species in a relatively short time. Furthermore,
recombinant DNA methods broaden the number and type of genes potentially
available for use; no longer is a project dependent upon the intrinsic genetic
variability of the species under study.
After the development of
P
-element-mediated transformation of
D. melano-
gaster
in 1982, many speculated about the role that molecular genetics could
play in the genetic control of vectors of human and animal diseases or pests of
agricultural crops (
Crampton et al. 1990, Eggleston 1991, Richards 1993, Curtis
1994, Gwadz 1994, Beaty 2000, Beard et al. 1992, 1993, 2000, Blair et al. 2000,
Collins 1994, Durvasula et al. 1997, Collins et al. 2000, Aksoy et al. 2001, James
2000, 2001, Robinson and Franz 2000
). Some considered transgenic technology
to be a new and vitally important pest-management tool for the control of seri-
ous pests that cannot be controlled by any other means. Others expressed reser-
vations about the goals and the methods to be used (
Spielman 1994, Curtis and
Townson 1998, Curtis 2000, Knols et al. 2006
) (discussed further in the sections
on Risk Analysis [Section 14.11] and Regulatory Issues [Section 14.13]).
There are limitations to molecular-genetic methods at present that require
additional research. For example, traits primarily determined by single major
genes are most appropriate for manipulating insects by recombinant DNA tech-
niques at present. Methods for manipulating and stabilizing traits that are
