German researchers have installed the human version of the FOXP2 gene into mice and they sound different than normal mice. FOXP2 is required for articulate speech. The version of the FOXP2 gene in chimpanzees, our closest evolutionary relatives, differs by just two amino acids from the human version. The mouse version differs by three. Recent research finds that Neanderthals had our version, suggesting that they might also have been language users. As the New York Times reports:
[The] possession of the human version of FOXP2 does in fact change the sounds that mice use to communicate with other mice, as well as other aspects of brain function.
That is the result reported in the current issue of the journal Cell by Wolfgang Enard, also of the Leipzig institute, and a large team of German researchers who studied 300 features of the humanized mice. FOXP2, a gene whose protein product switches on other genes, is important during the embryo's development and plays an active part in constructing many tissues, including the lungs, stomach and brain. The gene is so vital that mice in which both copies of the gene are disrupted die after a few weeks.
Despite the mammalian body's dependence on having its two FOXP2 genes work just right, Dr. Enard's team found that 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, Dr. Enard says. Dr. Enard argues that putting significant human genes into mice is the only feasible way of exploring the essential differences between people and chimps, our closest living relatives.
FOXP2 induces significant changes in mammalian brains. Earlier this week, Japanese researchers showed that stable genetic modifications can be introduced into primates.So the question is: what would the effect of installing the human version of the FOXP2 gene into a chimp embryo be? How close to crossing the line between human and animal is ethical?
In a column back in 2004, while reporting on some earlier FOXP2 research, I mused on the question "What Is Too Human?" and concluded:
As humanity's biotechnological prowess increases, we will confront again and again the question of what, if any, limits should be placed on research that mixes human and animal genes, cells and tissues. The main ethical concern about such research is not the creation of improved and useful animals, but the risk of producing what would be, in effect, diminished human beings.
Creating mice that squeak differently is nowhere close to that ethical line and could shed fascinating light on what makes humans different.