When a certain gene is turned off in mice, it damages the stem cells that give hair its color—but not the regular color-making cells—so the hair gradually loses pigment and turns gray or white.

Mice without a certain gene have more harmful molecules in their hair color stem cells when their hair is growing, which might be why these cells get damaged.

When a certain gene is turned off in hair color cells in mice, their fur starts to gray early because the cells die off — but the ones that survive can still make pigment just fine.

Hair turning white in mice with a certain gene problem isn't because pigment-making cells stop working — in fact, when scientists reduced that gene in pigment cells in a dish, they made *more* color, not less.

In mice with a broken Dguok gene, their hair turns gray because the stem cells that give color to hair disappear early, even before the color actually fades.

In mice with a genetic problem that causes gray hair, giving them an antioxidant called NAC in their water seems to help keep their fur from turning gray by protecting the cells that give hair its color.