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.

When a certain gene is turned off in pigment cells in mice, their fur starts turning gray around 4 months old, and by 8 months, most of their hair has lost color — but normal mice don’t go gray, so this gene might help keep hair colored.

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.

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.

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.