Increases in the concentration of just two chemicals can result in dramatic facial changes

Published: Thursday 31 January 2002

Beauty might be just two molecules deep. This has been proved by a recent experiment, wherein, researchers caused chicken embryos to develop a second beak. To accomplish the feat, researchers from the University of British Columbia in Vancouver, Canada, manipulated cells that become part of the beak's front end when it develops. This resulted in the birds developing a twin egg tooth that plays a crucial role in opening the shell of the beak during its development. "We transformed one part of the face into another," says Joy Richman, a researcher at the university (www. nature.com, December 20, 2001).

The researchers were able to introduce the changes by increasing the concentration of two chemicals, which are made while the beak develops. The concentration of these two has a major influence on facial cells' eventual fate. One blocks the action of a protein that stimulates bone growth. The other, retinoic acid, is related to vitamin a and turns on the genes. Because of such characteristics, during the researchers' experiment, these two chemicals transformed the patterns in which bone and some tissues of the beak were laid down.

"The discovery that such a simple change can have such a dramatic effect is quite spectacular," says embryologist Claudio Stern of University College London, the uk. When facial development goes awry, the result can be deformities such as cleft lip. The discovery may not directly aid the understanding of facial deformities, but it might lead us to the mechanisms that fine-tune small areas of the face. However, according to some critics, more research needs to be done to draw substantial conclusions. They opine that a complex interplay of many factors controls facial development and the molecules alone cannot cause the transformation. "It's a major step forward, but there are other interpretations," says Philippa Francis-West from the King's College, London, the uk. She suggests that cell duplication rather than transformation can cause two front beaks to form.

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