ROBERT SIEGEL, host:
Tears are a part of life. Not only do they help lubricate the eyeball, but they're also a significant way we express emotion. Of course, there are times when tears are unwelcome.
And now, scientists in New Zealand may have found a way to eliminate them from one aspect of our lives.
NPR's Joe Palca has that story.
JOE PALCA: Sometimes, we humans deliberately seek out things that will make us cry. Think "Gone with the Wind."
(Soundbite of movie, "Gone with the Wind")
Ms. VIVIEN LEIGH (Actor): (As Scarlett O'Hara) Rhett, Rhett, where are you going?
Mr. CLARK GABLE (Actor): (As Rhett Butler) I'm going to Charleston, back where I belong.
Ms. LEIGH: (As Scarlett O'Hara) Please, please take me with you.
PALCA: Or "Casablanca."
(Soundbite of movie, "Casablanca")
Mr. HUMPHREY BOGART (Actor): (As Rick Blaine) If that plane leaves the ground and if you're not with them, you'll regret it. Maybe not today, maybe not tomorrow, but soon, for the rest of your life.
Ms. INGRID BERGMAN (Actor): (As Ilsa Lund) What about us?
Mr. BOGART: (As Rick Blaine) We'll always have Paris.
PALCA: But there are other times when crying is just a pain.
(Soundbite of slicing)
PALCA: Like making dinner and a recipe that calls for chopped onions. Wouldn't it be great if someone would invent an onion that didn't make you tear up? Colin Eady might be that someone. He's a plant geneticist at Crop & Food Research in New Zealand. He's developed a genetic tool kit to manipulate the genes in onions. His primary work is on making onions disease-resistant.
Dr. COLIN EADY (Geneticist, Crop & Food Research): When we developed the technology, then, to be able to manipulate onions, it became obvious that there were other things that we could also do.
PALCA: It turns out, there's a gene that makes an enzyme that's one component of the way onions make you cry. The other component is the sulfur compounds inside onion cells.
Dr. EADY: In a normal, healthy cell, the two components are kept separate.
PALCA: But when you chop an onion...
Dr. EADY: Then the two components, the enzyme comes together with the sulfur compounds in the cell and creates the tearing agent.
PALCA: But if you block the gene that makes the enzyme, no tears. So Eady and his colleagues pulled out their genetic tool kit.
Dr. EADY: We've come up with an onion in which we've sawn off that gene and we have no tearing agent.
PALCA: They can use instruments to show the tearing agent is not there, but they've also used human volunteers.
Dr. EADY: We can take the crushed onion extract and put it under your eye and you get no tearing whatsoever.
PALCA: Eady says the genetically modified onion should taste the same as a normal onion. But it will be awhile before his onion makes it to market if it ever does. The genetic tools he used to silence the gene would have to be proven safe for human consumption. He'd like to find a way to get the same result with conventional breeding, but even then it would take at least a decade before a crop is ready.
Dr. EADY: That's because onions take two years to go from seed to seed. So, it's going to take a long while to breed it in any way.
PALCA: Still, it would be nice to contemplate a day when tears are more common in the movie theater than the kitchen.
(Soundbite of movie, "Casablanca")
Mr. BOGART: (As Rick Blaine) Here's looking at you, kid.
PALCA: Joe Palca, NPR News, Washington.
NPR transcripts are created on a rush deadline by Verb8tm, Inc., an NPR contractor, and produced using a proprietary transcription process developed with NPR. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.