A single DNA base-pair change that influences differences in hair color is reported in a paper published online this week in Nature Genetics. The study explains the association of a nearby gene, KITLG, with blond hair color.

KITLG is an essential gene needed for development of many different cell types in animals and humans. David Kingsley and colleagues investigated the association between the KITLG gene and blond hair color, which has been reported previously. They found that a small change in a DNA sequence (known as an enhancer), far from KITLG, changes how strongly KITLG is expressed in hair follicles. Mice with the “blond” version have lighter, golden-brown fur, compared to the dark fur in mice with the other version.

The results help explain how an essential gene like KITLG can be involved in the control of hair color.