The G-netics of dark skin

Several mutant strains of mice have dark skin pigmentation due to an aberrant accumulation of pigment-producing melanocytes in the dermal layer of the skin. A new study shows that three such strains carry activating mutations in the genes encoding the G-protein subunits Galphaq or Galpha11, resulting in more pigment cell precursors and an excess of dermally retained pigment cells at birth.