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Evidence 2. SCIENTIFIC AMERICAN BLOGS
Jellyfish Genes Make Glow-in-the-Dark Cats
By David Biello | September 12, 2011
This research is about glowing cats. Yes, glowing
cats! The story starts NOT with cats but with
jellyfish.
Jellyfish are strange-looking creatures that live in
the ocean. Some kinds of jellyfish produce a
protein called the Green Florescent Protein, or
GFP for short. Jellyfish with GFP in their cells glow.
(Proteins are a kind of chemical structure.)
Here’s a picture of a glowing jellyfish. The green
glow is produced by the GFP protein in the cells,
which glows under UV light.
Each person: Ask your group one question about what you have
read to check understanding. Make sure you all understand the
answers to each person’s question.

So what do glowing jellyfish have to do
with glowing cats?
Here is what scientists did.
Scientists think that the protein is produced by a jellyfish gene.
They call this gene the GFP gene, and they think that the GFP
gene gives the cell instructions to make the GFP protein. (Genes
are made of DNA.)
They used a procedure that can take a gene from one animal
and put it in another animal.
The scientists took GFP genes from the jellyfish and injected
the jellyfish genes into unfertilized cat eggs. So the jellyfish gene
became a gene in these cats’ egg cells.
First: Each person: Ask your group one question about
what you have read to check your understanding. Make
sure you all agree on the answers to each person’s
question. If you are not sure, read again.

Second, discuss: What do you think will happen to the
cats?

We will illustrate what they did here.
Click on the jellyfish to see the first step.

Scientists took the GFP gene out of the jellyfish.
Discuss what you think the next step was.
Then click on the gene to see the next step.

The scientists injected the GFP gene
into an egg cell from a cat.
Discuss what you think the next step was.
Then click on the gene to see the next step.
Egg cell from
a cat

The egg cell with the GFP gene was fertilized
and developed into a
glowing cat.
Egg cell from
a cat


Which one of these is correct?
Scientists took
the GFP gene
from a jellyfish
GFP gene was
injected into an
unfertilized egg
cell from a cat
The cat egg was
fertilized and
developed
Glowing
cat!
Scientists took
the GFP gene
from a glowing
cat
The cat egg was
fertilized and
developed
GFP gene was
injected into the
cat
Glowing
cat!
Scientists took
the GFP gene
from a jellyfish
The cat egg was
fertilized and
developed
GFP gene was
injected into the
cells of an adult
cat.
Glowing
cat!

Nice Job!

TRY AGAIN!
Click back to read what the scientists did
again and try again.
BACK
Make two predictions
1. Do you think the scientists found the
GFP gene in the adult cat cells?
2. Do you think the scientists found the
GFP protein in the adult cat cells?
Discuss reasons for your answers!


Yes! The cats’ cells all had the gene for GFP, and their
cells also had the GFP protein.
The result is that cats glowed green under UV light the
same way the jellyfish does! Normal cats never glow under
UV light.
Conclusion: The GFP gene gives instructions to make the
GFP protein, which made the cats glow.
Question: Why are these cats glowing?
Make sure you all completely agree on
the answer and understand it fully.

Question: Do Question 6 on page 36.