When you Google “genetically modified organism,”
or “GMO,”
scary images like this one are among the first hits.
But, they don’t really tell you anything
about what GMOs actually are, so that’s
what we’re going to do in this episode of
Science IRL!
We’re going to show you how we make genetically
modified plants in the lab
(spoiler alert: it doesn’t involve syringes filled with mysterious rainbow chemicals)
and discuss whether they’re safe to eat.
And, we’ve provided a list of references
on these topics and others in the description
if you’d like to know more!
**intro music**
Molly: Welcome back to Science In Real Life!
I’m Molly, and we’re here at the Boyce
Thompson Institute located on the campus of
Cornell University in Ithaca, New York.
And this is our super special guest, assistant
professor Joyce Van Eck
Joyce: Hi!
I’m a plant geneticist, and I use genetic
engineering to help improve crops to be more
resistant to insects, diseases, have a higher
nutritional content, and be more productive.
M: So yes, this episode is all about genetically
modified organisms, or GMOs.
We’re going to explain the science behind
GMOs, and actually get to make one in the lab.
We’d really like to de-mystify this technology
for you guys.
Well, first things first- what’s a GMO?
J: A GMO is any organism that’s had its
DNA changed.
Depending on what trait we want to get, we
can put DNA in from another organism, we can
make more copies of a gene that’s already
there, or we can turn off a gene.
M: Right, so GMOs have DNA.
But so does every single organism on this
planet!
Bacteria, fungi, plants, humans- we all have
DNA, and GMOs are no different.
So why do we make GMO crops?
J: Well, we can use GMOs to help solve some
major problems in agriculture.
We can increase yield, we can make crops more nutritious,
and we can make them more resistant to disease and drought.
M: But, there is a lot of misunderstanding
about this technology, and it’s really easy
to be afraid of something that we don’t
understand.
So, we’re going to show you how this technology
works- we’re going to make a GMO right now!
J: So today we’re going to make a genetically
modified tomato – we’re going to make
more copies of a gene that’s already inthe plant that will help it make more flowers, and more fruit!
For this experiment, my research assistant
Cynthia is going to help us out.
M: Great! Let’s get started!
Cynthia: Hi! I’m Cynthia. Today we’ll be genetically modifying some tomato plants,
and it’s also a process called ‘transformation.’ Would you like to help?
M: Definitely!
C: These are the plants we’ll be transforming.
Now we’ll be cutting up some cotyledons.
M: And cotyledons are the first leaves that
a seed puts up
C: And we’re using such young plants because
they're simply the best for this process
M: Hey guys, you ready?
C: And all we need to do is cut them- and
you can try the next one!
M: It’s like chopping up the tiniest salad.
C: Now that we’ve cut up the cotyledons,
we can transform them by using agrobacterium!
M: Agrobacterium is a bacterium that has naturally
evolved a way to genetically modify plants.
It’s found in the soil, and when it gets
into plants through their roots, it forces
the plant to make all the things the Agrobacterium
needs to grow and be happy.
It does this by transferring a tiny piece of DNA called a “plasmid” into the plant cell.
Agrobacterium proteins then insert the plasmid
into the plant’s DNA, causing the plant
to start producing food and housing for the bacteria.
Scientists have figured out a way to harness
this ability to create GMOs.
So, rather than putting its own DNA into the
plant, we can make the Agrobacterium put the
DNA that *we* want into the plant instead.
We simply give it a different plasmid, which
contains genes to help the plant become drought
tolerant, or resistant to disease, or in this
case, to produce more flowers and therefore more fruit.
The Agrobacterium really does all the work!
C: So I've grown up some Agrobacterium containing
the plasmid
M: So all that cloudy stuff is the Agro?
C: Yes!
M: And we’ll be using it to transform our
tissue?
C: Exactly.
So I've made up a solution containing the
Agrobacterium- Now we toss the cotyledons
right in there, and shake them.
M: (laughs) Plant transformation is happening
right now??
C: Science!
M: I’m making a GMO right now??
C: Exactly.
Now that the cotyledons are coated in Agrobacterium,
we’re going to put them on a plate and into
an incubator for 2 days, and that’s where
the magic happens
M: And now they’re ready!
C: now that the tissue has been transformed, we can move them to a medium that contains two things.
The first is an antibiotic, which will kill off all the Agrobacterium
M: so the Agro has done its job, and we don’t
want it hanging around any more
C: Yup.
The second thing is a plant hormone, that
will turn that tissue into an entire plant
M: Wow. So plants are amazing – this is not something that only genetically modified organisms can do.
All plants have the ability to regenerate
a whole plant from just a little bit of tissue
if they're given the right hormonal signals.
And now that the cotyledons are on the media,
we bring them to the growth chamber where
they can regenerate into tomato plants.
C: these are the cotyledons that we just transferred.
And these are a later stage where you can
see little plants popping up.
And these are a much later stage.
And now you see them rooting!
M: Oh it looks just like a tomato plant! Cuz it is!
So how do we know that our transformation was successful
and that our tomatoes are now genetically modified ?
J: Well we did a DNA Extraction and we used
PCR to test for the presence of the marker.
**groovy PCR music**
And you can see here in these four plants,
you can see the maker, but it’s not in the non-GMO plant.
M: Joyce is using the word ‘marker’ to
refer to a portion of our plasmid DNA.
These markers have unique sequences that are
a sort of beacon that we can use to test if
our transformation worked.
So if we find the marker sequence in our tomato,
we know it was successfully genetically modified
M: we covered DNA and PCR in season 1, so check out the links to those episodes if you want to know more!
And how do we know that the GM is actually
doing what we want it to do?
J: We transfer the plants to the greenhouse,
and after a few months we count the number
of flowers, and then several months later
we count the number of fruit.
We know it worked if the GMO plant has more
flowers and fruit than the non GMO plant.
M: Makes so much sense.
But how do we know that the genetic modification
isn't also doing something we *don’t* want
it to do?
J: Well we look at the plants and make sure
that the GMO plant looks exactly the same
as the non GMO plant except for the modification
that we made.
And we’re using this for our own basic research,
but if we were making a product, it would
be under evaluation by the United States Department
of Agriculture and the Food and Drug Administration
to make sure there were no hazards.
M: Long before it was ever released to the public?
J: Long before.
And if I felt there was anything harmful
that could come from doing this type of work, I wouldn’t be involved in doing it.
M: Of course.
M: So there are some common concerns that
people have about GMOs, like: ‘if I eat
a GMO, will it poison me or give me cancer?
J: No, GMOs have been tested for 20 years and have never been shown to be poisonous or cause cancer.
M: OK, but if I eat a GMO, and the GMO has had its DNA changed, cant it change *my * DNA?
J: No, because the method that we use to genetically
modify an organism does not give that organism
the ability to genetically modify another organism.
And, the material that we use to modify a
crop is gone before it goes to market.
M: As a quick reminder, we did this when we transferred the cotyledons to the media containing antibiotics.
So that gets rid of the Agrobacteria, because they’ve done their job and we don’t need them anymore. 
Sorry, guys.
M: And how is the tomato we made today part
of your broader research program?
J: Well we hope what we learn in tomato can
be applied to other crops to increase yield,
to make more food, to feed people!
M: Joyce, this was really eye opening!
I think it's so important for people to know
how GMOs are made, how this technology is
used, and where their food comes from- thanks so much for taking the time to explain all this to us.
J: Oh I was happy to help!
M: If you want to know more about Joyce's research, you should click the link to her lab website, 
it's in the description.
And click over here to subscribe to Science
IRL, and don't forget to check out all those
resources in the description if you want to
know more about GMOs.
We'll see you next time!
This episode was brought to you by the American
Society of Plant Biologists,
The Boyce Thompson Institute,
and the European Society for Evolutionary
Biology
