[The following is an exact transcript of this podcast.]

Now, here’s something you don’t see every day: scientists cure color-blind monkeys. According to a report published online in the journal Nature, researchers have used gene therapy to allow color-blind squirrel monkeys to look at their fruit in a whole new light.

In one type of squirrel monkey, the males lack a visual pigment called L-opsin. Its absence renders the monkeys color-blind, unable to distinguish reds and green. Most of the females, on the other hand, see in full color. So the scientists got to wondering: what would happen if they gave a boy squirrel monkey the same opsin that girls have.

Using a harmless virus, the scientists introduced the pigment gene into the eyes of color-blind adults. Lo and behold, about a month later, the monkeys with the new L-opsin gene were able to see hues they’d never seen before.

The research doesn’t mean we’ll soon be trying the same thing in humans. Because we’re not yet ready to monkey with our own selves that way. But the fact that a fellow primate was able to make and use the new pigments, even though they received the genes as adults, was a real eye-opener.

—Karen Hopkin

For more on this monkey business, go to Gene Therapy Cures Color-Blindness in Adult Monkeys

[Scientific American is part of the Nature Publishing Group.]