Why do hair turn grey

Scientists have pinpointed the cells that cause hair to turn gray and to go  bald in mice, according to a new study published in the journal Genes &  Development. Researchers from the University of Texas Southwestern Medical Center  accidentally stumbled upon this explanation for baldness and graying hairs-at  least in mouse models-while studying a rare genetic disease that causes tumors  to grow on nerves, according to a press release from the center. They found that a protein called KROX20 switches on skin cells that become a  hair shaft, which then causes cells to produce another protein called stem cell  factor. In mice, these two proteins turned out to be important for baldness and  graying. When researchers deleted the cells that produce KROX20, mice stopped  growing hair and eventually went bald; when they deleted the SCF gene, the  animals' hair turned white. "Although this project was started in an effort to understand how certain  kinds of tumors form, we ended up learning why hair turns gray and discovering  the identity of the cell that directly gives rise to hair," said lead researcher  Dr. Lu Le, associate professor of dermatology at the University of Texas  Southwestern Medical Center, in a statement. More research is needed to understand if the process works similarly in  humans, and Le and his colleagues plan to start studying it in people. "With  this knowledge, we hope in the future to create a topical compound or to safely  deliver the necessary gene to hair follicles to correct these cosmetic  problems," he said