May 29, 2009
Mice Given Human Speech Gene
German researchers have given mice the so-called "language gene" in an effort to understand the evolution of language.
While the genetically-altered mice can't speak, they squeak differently and their brain circuits are measurably different "“ offering insight into how the gene works and how it evolved.
The language gene, FOXP2, was first identified in 1998 when researchers discovered that members of a large family with a speech impediment had defective copies of the gene. The gene is present in primates and other mammals, but it takes a unique form in humans, which was replicated in mice for the study.
"Changes in FOXP2 occurred over the course of human evolution and are the best candidates for genetic changes that might explain why we can speak," said Wolfgang Enard of the Max Planck Institute for the Study of Anthropology, who led the study's research team. "The challenge is to study it functionally."
In the genetically-altered mice, the brain circuits observed were different than those of unaltered mice, in ways that mimicked the brain circuits associated with language in humans. In addition, the vocalizations of mice with the genes had different ultrasonic qualities. Enard cautioned that not enough is known about mouse communication to draw firm conclusions on the sound difference.
While mice are further from humans than chimpanzees, genetically speaking, their similarities make for a useful comparison. "In the last decade or so, we've come to realize that the mouse is really similar to humans," Enard noted. "The genes are essentially the same and they also work similarly."
Past research on FOXP2 indicates that the human version has two amino acid substitutions compared to that of chimpanzees.
Previous studies concluded that the human variation of the gene was selected for because it influenced important aspects of speech and language.
The report can be found in the May 29th issue of the journal Cell.
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