Sidebar: Dentist-Scientist Tracks Craniofacial Development

Three quarters of all birth defects in humans disrupt the normal formation of a baby's head and face.

Such malformations have serious effects on quality of life and can impact disease risk, since the bones of the head protect the brain and most of our sensing mechanisms that detect the outside world, eat, breathe and talk.

Researchers know that one of the first steps in the early development of the head and face is the formation of a special set of cells called the cranial neural crest. As an embryo develops inside its mother, subsets of these neural crest cells receive molecular signals prompting them to form bone, cartilage, or teeth that then go on to form specific parts of the head and face.

Developmental biologist Yang Chai, D.D.S., Ph.D., of the University of Southern California in Los Angeles, is creating cutting-edge molecular tools to track the fate of neural crest cells and determine which molecules push them to become particular tissue types.

For example, Chai has used genetically engineered mice to pinpoint the roles of certain growth factors critical for the proper formation of the teeth, jaw, and palate (roof of the mouth). By switching on or off the production of the genes that encode the growth factors, Chai has learned which ones are used by the neural crest cells to make specific craniofacial tissues. His research team is now working on how to manipulate the expression of these growth factors in an effort to fix cleft palate in living tissues.