Imagine having GeneVision: the uncanny ability to view the activity of any chosen gene in real time through a specially modified camera.
With GeneVision, military commanders could compare gene expression in victorious and defeated troops. Retailers could track genes related to craving as shoppers moved about a store. "The Bachelor" would enjoy yet one more secret advantage over his love-struck dates.
Frightening? Perhaps. Ethically suspect? Certainly. Preposterous? Not quite.
A new study in BMC Biotechnology correlates real-time gene expression with movement and behavior for the first time. The proof-of-concept experiment in fruit flies opens a new door for the study of genes' influence on behavior.
The authors, from the University of Southern California and Cambridge University, tagged genes with a harmless molecule known as Green Fluorescent Protein (GFP).
When a gene was active, the flies gave off a fluorescent glow. A camera fitted with a special filter detected the glow, whose intensity was then measured automatically.
At the same time, a multiple-camera system designed by first author and USC graduate student Dhruv Grover tracked the movement of each fly in three dimensions.
The result: an exact picture of gene activity at every point and time of a fly's life.
"We can correlate behavior with certain genes and find genes that may be responsible for certain behaviors," Grover said.
The 3-D tracking and real-time measurement of gene activity are both firsts in live animal studies, the researchers said.
The methods also delivered new insights on aging in the fruit fly, long a model organism for the study of biological processes.
The levels of two genes, hsp70 and hsp22, spiked in the hours before the death of a fly.
The genes are known to respond to oxidative stress. Lead author John Tower, associate professor of molecular and computational biology at USC, speculated that the genes were reacting to a sharp increase in oxidative stress as the fly began dying of natural causes.
"We're really interested in why the fly is dying, and this is potentially a good inroad to being able to study that," he said.
Oxidation – the chemical process behind rust and food spoilage – takes place constantly in the body as a byproduct of metabolism.
"Burning that fuel to produce energy is toxic," Tower said.