While most people will experience a hair color change to grey as they get older, it's not simply a matter age making the hair lose pigment. The stem cells at the base of hair follicles produce melanocytes, the cells that create and store pigment in hair and skin. The death of the melanocyte stem cells causes the onset of graying. What hasn't been well understood is why the cells in one hair will die off, but another follicle less than a millimeter away stays the natural color for much longer.
New research from University College London has found that it's not merely random cell death but rather a genetic factor. Looking at several thousand people of different ethnic backgrounds in Latin America and discovered that the IRF4 gene, which was known to be involved in hair color, was also a major part of when and how a person's hair would turn grey. Having found which gene causes the greying process, scientists believe that it could someday be manipulated to either reverse or stop the progression of grey hair.