How does neoteny affect people's thinking?

Scientists noticed decades ago that adult humans resemble young chimpanzees in appearance. Both have narrow teeth, a flat face, and sparse body hair. The retention of childlike characteristics - evolutionary biologists speak of neoteny - also occurs in domestic animals: thanks to human preferences, for example, many dog ​​breeds show characteristics of puppies such as floppy ears, short snouts and large eyes.

Scientists have now found genetic evidence that neoteny could partially explain why chimpanzees and humans differ so greatly, even though they largely coincide in terms of their genetic makeup and only diverged around six million years ago - which is a short period of time in evolutionary terms.

In general, neoteny is based on delays in individual development. Humans only reach sexual maturity as chimpanzees around five years later and keep their milk teeth longer. "Changes in the development schedule are among the most effective mechanisms of evolution to transform organisms," explains molecular biologist Philipp Khaitovich from the Max Planck Institute for Evolutionary Anthropology in Leipzig. "It only requires a few molecular events."

Looking for genetic clues that neoteny has a role in the evolution of the homo sapienshas played, the researcher and colleagues compared the activity - more precisely, expression - of 7958 genes in the brains of 39 people, 14 chimpanzees and nine ...

This article is featured in Spectrum of Science October 2009