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Trudy Mackay displays a tray of fruit flies in the cultivation room in Thomas Hall on Nov. 7. The climate controlled room allows the fruit flies to mature in optimal conditions. Photo by Tyler Andrews.
Trudy Mackay and Robert Anholt , genetics professors, started their work on fruit flies looking for genetic links to aggression, but after some time in the lab with these little insects, they found links to human aggression.
With a team of geneticists from Belgium, the researchers carried out a study to discover the basis of aggression in fruit flies. Mackay and Anholt , with a team of graduate students from the genetics department, investigated the genetic basis of aggressive behavior in the Drosophila species of fruit flies.
The behavioral patterns in fruit flies are found to be similar to that of humans.
“Enough resources regarding the genetics of fruit flies are available,” Mackay said. “They show certain behavioral patterns, similar to humans like longevity, stress resistance and aggression, the study on which can help solve problems in human genetics.”
The aggression in fruit flies can be seen through two controlled variables—induced mutations and natural variation. This research dealt with the effect of six types of induced mutations on the behavior of the flies.
“We did not expect so many combinations of the mutations and their combined effect on the fruit fly aggression pattern,” Mackay said. “We could observe various types of aggression in flies like chasing other flies, wing threat, kicking, boxing and sometimes even a tussle. The aggression in fruit flies was easily visible as they even went to the extent of grabbing each other and engaging in a fight.”
Liesbeth Zwarts , a graduate student from Belgium working with researcher Patrick Callaerts , was the lead author of this research. The main question at the start of the project dealt with whether the mutations shall have their effect independently on the brain of the fruit fly, or have a combined effect. They found out that all the six mutations showed a multiple combined effect on the brain behavior, which is a phenotypic change.
According to “Scitable ,” by Nature Education, this effect of masking the effect of another gene or having a combined phenotypic effect through multiple genes is known as epistasis . Investigator Liesbeth Zwarts found out that the combined effect of 6 mutations due to epistasis was found to target the α-(alpha)-lobe in the mushroom body in the brain of the fruit fly.
According to Mackay, this research is shown to have large impacts in the medical research field in human genetics.
“If a large number of loci is found to be similar in fruit flies and humans, then genetic basis of incurable disorders like Alzheimer’s and frequent mood shifts in humans can be found out,” Mackay said. “The genes controlling the nervous system are well conserved during evolution. Hence this research is expected to possess large implications in the treatment of neurogenetic disorders.”
Like most of the genetics research, this one too started with fruit flies. Further research is to be carried on in mice, rats and later humans.
“NMDA and serotonin neurotransmitters and receptors which are possessed by fruit flies, mice, rats as well as humans can lead to developmental research for human genetics,” Mackay said. These receptors help control signal transduction pathways, which control cellular responses to various stimuli.
According to Sumanas Inc. Neurobiology multimedia publishers, some neurotransmitters like serotonin, and receptors like NMDA ( N-methyl-D-aspartate ) control synaptic plasticity and memory control. Hence the implication of this research is assumed to be widespread.
The Belgian scientists and geneticists of N.C . State are still working on the next part of this research. Just like induced mutation, they now hope to study other behavioral effect in fruit flies.