Biology Reference
In-Depth Information
determined by complex genetic mechanisms are not yet feasible with insects,
although such methods could be developed using procedures developed by
plant molecular geneticists as models.
Genetic manipulation of arthropods involves several steps and requires sub-
stantial investments of time and resources to answer the questions in Table 14.2 .
A successful project outcome requires that we have a thorough knowledge of
the biology, ecology, and behavior of the target species. Identifying one or more
specific traits that, if altered, potentially would achieve the goals of the project
is a critically important planning step. If the nuclear genome of the target spe-
cies is to be modified, suitable genes must be identified and cloned and appro-
priate regulatory sequences must be identified so that the inserted gene will be
expressed at appropriate levels in the correct tissues and at a relevant time.
Table 14.2: Questions to Answer when Developing a Genetic Manipulation Project if it is to be
Deployed Successfully.
PHASE I. Defining the problem and planning the project
l
What genetic trait(s) limit effectiveness of beneficial species or might reduce damage caused by the pest?
Do we know enough about the biology, behavior, genetics, and ecology of the target species to answer
this question?
Is the potential trait determined by single or multiple genes?
l
Can alternative control tactics be made to work more effectively and inexpensively than genetic
manipulation projects, and are they more environmentally friendly?
The costs of genetic-manipulation projects are high and the time to develop a functional program can
be quite long.
Transgenic or paratransgenic technology may not be appropriate if traditional genetic or other control
methods can be used because issues surrounding risk assessment of releasing transgenic arthropods
into the environment for permanent establishment have not been resolved.
l
How will the genetically manipulated strain be deployed?
Will releases be inoculative and some type of selection or drive system used to replace the wild strain?
Will the desired genes be introgressed (introduced) into the wild population? What selection
mechanism will be used?
Will augmentative releases of very large numbers be required?
Will multiple releases be required over many years?
l
What risk issues should be considered in planning?
If pesticide resistance genes are used as a selectable marker or useful trait for beneficial species, is
there a possibility of the resistance gene moving to a pest?
What is known about the potential for horizontal transfer?
If TE or viral vectors are used in the transformation process, what risks might they pose if the
transgenic strain is released into the environment?
What health or other hazards might be imposed on human subjects if the genetically modified strain
were released?
l
What advice do the relevant regulatory authorities give regarding your plans to develop a genetically
modified strain?
Which agencies are relevant to consult for your project?
 
Search WWH ::




Custom Search