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...

When a specific gene needed for energy production in hair color cells is turned off in mice, the cells that give hair its color die off, causing the fur to turn gray over time.

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.

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 specific genetic problem, hair turns gray because the stem cells that make hair color die off first—not because the color-making process itself is broken.

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.