New research published in the journal Current Biology adds significantly to understanding of how the ear works, giving hope to millions of deaf and hard of hearing people.

The latest research, conducted by Dr Jörg T. Albert, a Deafness Research UK research fellow at the UCL Ear Institute, together with scientists at the University of Cologne, shows that fruit flies have ears which mechanically amplify sound signals in a remarkably similar way to the sensory cells found in the inner ear of vertebrates, including humans. The finding means the wealth of genetic techniques already available to study the fruit fly can now be used to target how the ear works.

"The biophysical parallels between the ways both fruit flies and humans convert sound into nerve signals are truly amazing," Albert says. "We may be allowed to hope that these mechanistic similarities extend further down to the genes and molecules that bring about hearing. But even if it finally should turn out that hearing in fruit flies relies on different molecules than does hearing in humans, the little fruit fly can help us find answers to some key questions of hearing research and—what is sometimes even more important—will surely help us ask the right questions."

Vivienne Michael, chief executive of Deafness Research says this is an important advance that paves the way toward a clear understanding of the genetics of deafness.

Björn Nadrowski, Albert, and Martin C. Göpfert report a mathematical model of the process, known as transduction, used by Drosophila melanogaster (the fruit fly) to transform mechanical energy from sound waves into electrical signals. In vertebrates this transduction is performed by hair cells which send the electrical signals on to the brain where they are understood as sounds. However, there are important structural differences between the inner ear of vertebrates and invertebrates like the fruit fly. These differences have lead researchers to believe that transduction must work on different principles.

The research team compared real data—from measurements of the amount of cochlear amplification found in the fruit fly inner ear—to the output of their model and found that around 20 transducers per sensory cell are enough to describe the real data accurately. This is the same as the number of hairs on a hair cell. Their results both describe the hearing organ comprehensively and open up the field of deafness research to Drosophila genetics. By manipulating the genes which control the transducers, scientists can identify which molecules are involved in allowing hair cells to send signals to higher brain centres.

[Source: Medical News Today]