story to find out more.
Paul Shirk (left) and technician Richard Furlong examine a genetically
transformed Indian meal moth caterpillar using fluorescence microscopy.
Click the image for more information about it.
Gene "Delivery Truck" Aids Nonchemical Pest
Control By Jan
Suszkiw September 8, 2006
In a pest-control approach called the sterile insect technique,
irradiation is used to sterilize factory-grown males of a pest insect, like
screwworms or Mediterranean fruit flies. When released into the field, the
males mate with wild females and no offspring are produced, thus eliminating or
reducing the need for chemical insecticides.
Over the past several years, Agricultural Research Service (ARS) scientists have conducted research
using molecular genetics to develop genetic systems to sterilize pest insects
instead of irradiating them. This new approach calls for using modified pieces
of DNA, called transposons, to introduce foreign genes that can cause sterility
in pest insects.
The trick is making sure the transposons don't move after they're
inserted into the insect's chromosomes. Otherwise, the sterilizing trait can be
Shirk, a physiologist with ARS'
for Medical, Agricultural and Veterinary Entomology in Gainesville, Fla.
As an alternative to using the transposons, Shirk and colleagues
disabled the machinery of a virus that infects the common buckeye butterfly and
turned the pathogen into a gene "delivery truck" called JcDNV. When
injected into an insect's embryonic stage, the JcDNV delivers its
loada foreign geneinto a chromosome. The gene stays put, and
scientists can monitor its activity throughout the insect's life, including
whether it passes the gene to offspring.
However, unlike the transposons, the JcDNV restricts its
deliveries to the insect's somatic (body) cells, but not its reproductive
cells, notes Shirk, who's in the ARS center's
Behavior and Biocontrol Research Unit.
Shirk collaborated with Max Bergoin, a virologist who originally
cloned the virus, Junonia coenia densovirus, at the
University of Montpellier in France,
and a postdoctoral team comprising Herve Bossin and Jennifer Gillett (both
formerly ARS), and ARS technician Richard Furlong.
about their work in the September issue of Agricultural Research
ARS is the U.S. Department of
Agriculture's chief scientific research agency.