His class at CU Denver is not in session, but Dr. Chris Phiel is ready to answer questions about a scientific breakthrough at Oregon Health and Science University over summer break.

“This is the first time in human embryos that something like this has been taken on and studied,” Phiel said.

A study, published Wednesday in the journal Nature, showed researchers successfully edited genes in human embryos in order to fix a disease-causing mutation.

“This has to do with this relatively new technique that was discovered a couple years ago called CRISPR,” Phiel explained. “CRISPR is a new way to precisely cut DNA.”

Researchers repaired a mutation that causes hypertrophic cardiomyopathy. The common condition can lead to sudden heart failure.

“What the new researchers tried to do was go in and correct that mutation so that the mutation wouldn’t be passed onto future generations,” Phiel said.

The CRISPR technique is kind of like finding a typo in a word document and correcting it.

“Except your word document has 3 billion letters in it,” Phiel said. “Go in and correct one letter that’s misspelled out of 3 billion and make it now make sense again.”

Gene editing could potentially protect babies from inheriting certain diseases. Of course, the discussion of genetic modification opens the door to an ethical debate.

“You do worry that once this technique starts to take off that people with start to use it for other things,” Phiel said.

In February, a panel from the National Academy of Sciences and National Academy of Medicine issued guidelines for researchers experimenting with gene editing in human embryos.

“It’s essentially for diseases that can’t be treated by any other means,” Phiel said. “But you worry over time that those guidelines will be relaxed a little bit and people will start to want to use this for other purposes.”

Phiel cited examples of gene editing used to make someone stronger or to change physical appearance.

“I think that going forward, we just need to be really careful about knowing how this technique is going to be used because not everybody is going to be as well-intentioned as these scientists were,” Phiel said.

Phiel teaches a class a CU Denver on gene editing where students use the CRISPR technique on mouse embryos. In the spring, one of the doctors who helped develop the gene editing method will come to speak at CU Denver.