Talking Mice Help Scientists Delve into the Makings of Human Language

The prospect of animal-lovers like Dr. Doolittle holding intra-species conversations just became a little more plausible. Although mice may lack the ability to say "Hello" and "Good-bye" as humans do, Svante Paabo and his team at the Max-Planck Institute for Evolutionary Anthropology in Leipzig, Germany have genetically engineered mice to contain a humanized version of a gene known to influence speech and language. The original mouse version of gene is remarkably 93.5% similar to the human variation and even more similar to the chimp version, but those percentage points make all the difference between the ability to recite Hamlet's soliloquy and the ability to merely squeak. While scientists recognize the differences, they are still trying to understand why, historically and evolutionarily, these differences exist and how exactly humans are able to talk.

One such distinction are two amino acid substitutions in FOXP2. Gene FOXP2, called "forkhead box P2," is involved in the advancement of language skills, including linguistic creativity and grammatical constructions. It developed in humans about 100, 000 years ago, around the same time that our ancestors began employing verbal language. FOXP2 is not exclusively responsible for our ability to speak--language is complicated enough that it requires the presence and proper functioning of multiple genes--but it still plays a crucial role. In 1998, scientists identified FOXP2 as the cause of a speech disability in a big London family; about half of the family struggled with grammar and articulating their words. After studying the family, Paablo and his team published an article about the gene's role in language in August 2002.

What is even more interesting than the fact that scientists were able to implant the "speak gene" into the mice is the fact that the mice used squeaks they were not naturally capable of producing. The scientists placed the baby mice outside of their mother's nest and studied the sounds they made. Based upon a qualitative assessment, the scientists observed that the engineered mices' ultrasonic vocalizations differed from those of their non-engineered peers. The engineered mice seemed to almost whistle. FOXP2, which is active in other body tissues besides the brain, only appeared to affect the mice on a vocal level. The engineered mice grew nerve cells more complex than normally found in mice.

Scientists, such as Wolfgang Enard, are excited about this genetic feat because it may help them trace the human history of language. Enard, who studies molecular comparisons between humans and chimpanzees in order to determine what distinguishes us from other primates, is not confident enough about what the changes between the engineered and non-engineered mice's vocalizations mean, however. The only certainty is that the team has taken an important step toward better understanding human language.

News References

"Why Can We Talk? 'Humanized' Mice Speak Volumes About Evolutionary Past.' ScienceDaily.com.

http://www.sciencedaily.com/releases/2009/05/090528120643.htm. Accessed 31 May 2009.

"From Genes to Words." http://www.corante.com/loom/archives/000811.html. Accessed 31 May 2009.

Wade, Nicolas. "A Human Language Gene Changes the Sound of Mouse Squeaks." The New York Times. http://www.nytimes.com/2009/05/29/science/29mouse.html. Accessed 29 May 2009.

Original Journal Reference

Enard et al. A Humanized Version of Foxp2 Affects Cortico-Basal Ganglia Circuits in Mice. Cell, 2009; DOI: 10.1016/j.cell.2009.03.041