Researchers have genetically engineered a strain of mice to carry the human version of a gene called FOXP2, which has previously been linked to speech. While other animals possess the gene, the human version varies slightly from those of both mice and chimpanzees. (Neanderthals appear to have the same version as modern humans.)

According to the New York Times, "the human version of FOXP2 seemed to substitute perfectly for the mouse version in all the mouse's tissues except for the brain."

In a region of the brain called the basal ganglia, known in people to be involved in language, the humanized mice grew nerve cells that had a more complex structure. Baby mice utter ultrasonic whistles when removed from their mothers. The humanized baby mice, when isolated, made whistles that had a slightly lower pitch, among other differences, says [Wolfgang Enard, a scientist at Max Planck Institute for Evolutionary Anthropology, in Leipzig, Germany, who led the work].

For more on the FOXP2 gene and the hunt for the genetics of language, check out this Technology Review feature by Jon Cohen, "The Genetics of Language."

When Monaco, Fisher, Hurst, and coworkers reported the FOXP2 findings in the October 4, 2001, issue of Nature, it made international headlines--and, more important, announced the start of a new era in speech and language research.

Even then, the scientists knew that FOXP2 does not single-handedl­y wire the brain for language. In the grand theater of the genome, it is cast as a transcription factor, turning other genes on or off by telling them whether to transcribe their DNA into messenger RNA, which leads to the production of proteins. And FOXP2 has a broad repertoire in embryonic development, playing critical roles in the formation of the lungs, heart, and intestines.