Why can we talk? 'Humanized' mice speak volumes

May 28, 2009

Mice carrying a "humanized version" of a gene believed to influence speech and language may not actually talk, but they nonetheless do have a lot to say about our evolutionary past, according to a report in the May 29th issue of the journal Cell, a Cell Press publication.

"In the last decade or so, we've come to realize that the mouse is really similar to humans," said Wolfgang Enard of the Max-Planck Institute for Evolutionary Anthropology. "The genes are essentially the same and they also work similarly." Because of that, scientists have learned a tremendous amount about the biology of diseases by studying mice.

"With this study, we get the first glimpse that mice can be used to study not only disease, but also our own history."

Enard said his team is generally interested in the genomic differences that set humans apart from their primate relatives. One important difference between humans and chimpanzees they have studied are two amino acid substitutions in FOXP2. Those changes became fixed after the human lineage split from chimpanzees and earlier studies have yielded evidence that the gene underwent positive selection. That evolutionary change is thought to reflect selection for some important aspects of speech and language.

"Changes in FOXP2 occurred over the course of human evolution and are the best candidates for that might explain why we can speak," Enard said. "The challenge is to study it functionally."

For obvious reasons, the genetic studies needed to sort that out can't be completed in humans or chimpanzees, he said. In the new study, the researchers introduced those substitutions into the FOXP2 gene of mice. They note that the mouse version of the gene is essentially identical to that of chimps, making it a reasonable model for the ancestral human version.

Mice with the human FOXP2 show changes in brain circuits that have previously been linked to human speech, the new research shows. Intriguingly enough, the genetically altered mouse pups also have qualitative differences in ultrasonic vocalizations they use when placed outside the comfort of their mothers' nests. But, Enard says, not enough is known about mouse communication to read too much yet into what exactly those changes might mean.

Although FoxP2 is active in many other tissues of the body, the altered version did not appear to have other effects on the mice, which appeared to be generally healthy.

Those differences offer a window into the evolution of speech and language capacity in the human brain. They said it will now be important to further explore the mechanistic basis of the gene's effects and their possible relationship to characteristics that differ between humans and apes.

"Currently, one can only speculate about the role these effects may have played during human evolution," they wrote. "However, since patients that carry one nonfunctional FOXP2 allele show impairments in the timing and sequencing of orofacial movements, one possibility is that the amino acid substitutions in FOXP2 contributed to an increased fine-tuning of motor control necessary for articulation, i.e., the unique human capacity to learn and coordinate the muscle movements in lungs, larynx, tongue and lips that are necessary for speech. We are confident that concerted studies of , humans and other primates will eventually clarify if this is the case."

Source: Cell Press (news : web)

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User comments : 9

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shavera
4 / 5 (1) May 28, 2009
Why not try inserting the human FOXP2 into, say... a chimpanzee? Wouldn't that be a much better guide to how this gene influences language?
WarRoom
not rated yet May 28, 2009
According to the NYT article, "There is no good way of genetically engineering chimps, even it were ethically acceptable, so the mouse is the testbed of choice, in Dr. Enard%u2019s view."

nkalanaga
not rated yet May 28, 2009
Part of the problem is that chimps reproduce slowly, so it would take a long time, while mice can go through several generations a year, and have multiple offspring in a litter. Also, mice are easier to catch and handle!

Besides, do you really WANT a talking chimpanzee in your lab? Suppose he started talking to the wrong people?
ArkavianX
not rated yet May 28, 2009
Is this the real "Secret of the NIMH?"

Discovery channel just ran a Monsterquest episode on NY giant rats too, lol...

Would be interesting to see results.
smiffy
3 / 5 (1) May 29, 2009
Maybe the real reason they don't implant chimps is that the chimp might tell us what he thinks of the conditions he's being kept in, and give his opinions on being genetically modified.
Icester
5 / 5 (1) May 29, 2009
What are we going to do tonight, Brain?
Same thing we always do... try to take over the world!

Do we _really_ want talking mice? Aren't we asking for trouble here?

nkalanaga
3 / 5 (1) May 29, 2009
Smiffy: My point exactly. Do we really want a talking experiment who's smart enough to really tell all?
tunasashimi
not rated yet May 31, 2009
The way I see it, is it's simply connecting autitory organs more directly to the brain.

The brain, being the magical multi-purpose device that it is, might start using whatever it connected to it, to it's benefit.

Just hooking up vocal cords to the brain, is not enough to get you talking however - that would take several generations of conditioning and possibly coordinating with other organs/muscles to get anything useful out of it...

My uninformed 2 cents ;)

And geez, why do u guys have to be so cynical? It would be amazing to have your horse be able to tell you why it's in such a bad mood today... thing is, it's more just about hooking up vocal cords... most animals can already make noises, its probably more about muscle control - and search on Youtube - it's just uncanny how certain dogs' barks sound like words and sentences when you play it in slow motion. There is one movie clip of a dog that speaks whole sentences, when played in slow motion... Super eerie!!

Point is, you don't need words to communicate.
nkalanaga
not rated yet Jun 01, 2009
That last line is true of humans, too. There are LOTS of ways to communicate without words. Domestic animals already do it with their humans.
And, it's been proven that dogs can understand several hundred words of their human's language, so speaking it wouldn't be a problem if they could talk.