1. 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.  1

2. 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?  

3. We will illustrate what they did here.
Click on the jellyfish to see the first step. 

4.  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. 

5.  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 

6. The egg cell with the GFP gene was fertilized and developed into a
glowing cat.
Egg cell from a cat  

7. Which one of these is correct?
GFP gene was injected into an unfertilized egg cell from a cat
Scientists took the GFP gene from a jellyfish
The cat egg was fertilized and developed
Nice Job!
Glowing cat!
Scientists took the GFP gene from a glowing cat
GFP gene was injected into the cat
The cat egg was fertilized and developed
Glowing cat!
GFP gene was injected into the cells of an adult cat.
Scientists took the GFP gene from a jellyfish
The cat egg was fertilized and developed
Glowing cat!  

8. Click back to read what the scientists did again and try again.

9. Discuss reasons for your answers!
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!  

10. 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 9 under Evidence 2. 