Scientists have used a gene identified in fruit flies to discover a crucial component of the origin of language in humans.
The evolution of language in humans continues to perplex scientists who study how humans learn to communicate.
Considered by some as "operant learning," this multi-tiered trait involves many genes and modification of an individual's behaviour by trial and error.
Now, using a gene identified in fruit flies by a University of Missouri researcher, scientists involved in a global consortium have discovered a crucial component of the origin of language in humans.
"By isolating the genes involved, we can uncover the biological basis of human language," said Troy Zars, associate professor of biological sciences in the College of Arts and Science at MU.
"In 2007, our team discovered that a gene in the fruit fly genome was very similar to the human version of the Forkhead Box P (FoxP) gene and in our latest study, we have determined it is a major player in behaviour-based, or operant, learning," said Zars.
The researchers studied flies in which the FoxP gene had been modified.
In a learning experiment that comes as close to simulating human language learning as possible, flies had to try different movements with their flight muscles in a custom-built flight simulator to learn where to fly and where not to fly.
The flies were trained to avoid flying in one direction, forcing them to try different steering manoeuvres.
The team found that flies with a compromised FoxP gene failed in the task, while flies with the uncompromised gene did well and learned their movements.
This learning deficit is conceptually similar to human patients with FoxP mutations, where communication is altered.
Subsequent tests showed a change in the structural makeup of the flies' brains indicating that operant learning depends on the function of this gene to develop normally.
These discoveries suggest that one of the roots of language can be placed 500 million years ago to an ancestor who had evolved the ability to learn by trial and error, the team said.
"These findings should help in understanding how genetic bases of communication deficits arise in humans," said Zars.
The study was published in the journal PLOS One.
