Name: What Is a Genetically Modified Food? - Instant Egghead #45
Uploaded: 2014-07-20T05:31:15.000Z
Duration: 3 min 14 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

In the last several years we've seen some strange genetically modified organisms.

Relative clauses (Restrictive vs. nonrestrictive)

Pigs that glow in the dark, chickens that grow without feathers,

and even goats that produce  spider silk proteins.

But what really gets people riled up are genetically modified foods.

The prospect of eating somebody's science project turns the stomach

of those who aspire to eat so-called "whole" or "natural" foods.

But what does "genetically modified" mean anyways?

To answer those questions we need to go back in time about 10,000 years.

That's when people first started domesticating animals

By picking organisms with desirable traits and mating them together

over and over again, people were able to mold species

The classic example is corn, which  started out as a tropical grass

called Teosinthe with small, nearly inedible kernels.

Over thousands of years, ancient farmers  in Mexico transformed the grass

into the delicious, starchy treat we like to eat today.

We now know those ancient farmers were manipulating

the long strands of DNA that encode for proteins

create the dramatic differences we see between Teosinthe

Scientists call this process "artificial selection,"

and it's made all kinds of  unappetising plants edible,

from wheat to rice to almonds and bananas.

What's different about modern genetically modified foods

is the speed and precision with which we can make changes.

Now, instead of selectively breeding for traits,

we can go directly to the DNA responsible, snip it out

and transplant it into newly developing plants and animals.

If these snippets come from the same species, scientists call the new

But if the DNA comes from a completely different plant or animal,

scientists call the new organism "transgenic."

Those florescent pigs, they glow green because they contain

And in the last 20 years, we've begun to see the food equivalent.

Corn that makes bacterial toxins poisonous to pests,

tomatoes that make the antifreeze proteins from fish,

So you may be wondering if this overt kind of manipulation is safe.

Well all of the GM foods currently on the market have been

But the verdict is still out on  some of the more exotic

Personally, I'm waiting for a tomato that I can cut in the dark.

For Scientific American's  Instant Egg Head,

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What Is a Genetically Modified Food? - Instant Egghead #45

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