Nerdette host Greta Johnsen has a rare genetic disease that CRISPR might be able to fix.

As a four-year old in Juneau, Alaska, Greta was diagnosed with an eye condition known as "Best disease." That name is somewhat of a misnomer in that "Best disease" causes premature macular degeneration — but curiously it happens to be among the best diseases for experimenting with CRISPR, a genetic engineering tool that can be used to edit DNA.

CRISPR has been in the news a lot lately (Google it) so we're rebroadcasting this very special episode, one that follows the story of Greta, her father, and Dr. Bruce Conklin, a scientist who's currently developing a CRISPR system to inject into some Johnsen family eyeballs. 

Plus, you can't have a conversation about experimental gene editing without discussing the ethical implications of making irreversible changes to human evolution. 

“We’d be permanently altering the course of evolution if we decide that we think it’s OK to edit human embryos," says Megan Hochstrasser, a science communications manager and CRISPR expert. "Is that something we want to be able to do as a society?”

That's a great question. Let's talk about it.