GloFish® really glow!

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Sandra Porter

Reposted in honor of the "glow in the dark" kitty clones.

Last year, I wrote about photographs of jellyfish that were altered by newspapers, scientific publishers, science education companies, and me (for the purpose of the article) to make it look like the jellyfish glowed.

Those jellyfish do NOT glow. Those images lie or at least misrepresent the truth.

But that doesn't mean that glowing animals don't exist. These pictures were taken under natural light and came from GloFish®.


Normally zebrafish are white with black stripes, but these zebrafish were genetically engineered to produce a fluorescent protein that makes the fish glow. The company web site doesn't identify the protein, but I would guess they use different mutant versions of green fluorescent protein (GFP).

Fish as pollution detectors
There's also an interesting story from the National University of Singapore about the development of these fish. The eventual goal is to use fish like these, as pollution detectors. The idea is that you could put detector fish into water, and if the water contained pollutants, the fish would glow. Environmental companies already do toxicity assays where they detect pollutants by putting fish into water. If the water contains harmful substances, the fish usually die or produce deformed offspring. Glowing fish could make the assay quicker. If toxic compounds can be detected more quickly, then rivers, streams, and lakes could be protected more quickly.

i-8d6f811e36eb5733b5c4defef09bdcb8-glofish_7_low_res.jpgHow would this work?
I'm cutting out a few steps, but this is the basic idea. Genes can be "turned on" or "turned off" when substances in the environment send the right kind of message to a cell. When the message is received, special kinds of proteins binds to specific sequences of DNA. These proteins attract other proteins, who make an RNA copy of the DNA. The RNA copy contains the directins for making the protein (GFP). GFP undergoes a chemical reaction and begins to glow.

The net result would be detector fish that would start to glow in the presence of harmful substances.

I don't know if the technology is worked out yet for the detector fish.

GloFish® on the other hand, are pets. They glow in clean water and live longer in clean water, too.

1. GloFish®
2. Zebrafish as pollution indicators, Natural University of Singapore, accessed Oct. 12, 2006.