Green pigs and journalist’s scientific illiteracy
I’m sure by now everyone has heard about the fluorescent green pigs produced by Taiwanese scientists. It’s a relatively simple technique, all one has to do is: transfect a plasmid containing the GFP and (maybe) am antibiotic resistance selector into very early embryonic stem cells, select using the antibiotic1 and the GFP, (That’s the easy part, the real trick is dealing with altered cells after transfection due to the funky, black box biology of stem cells) and allow to grow to term through implantation. This would give the uniform green “glow” that characterizes every cell of the animal.
As the article states, this has the potential of tracking how stem cells (used for therapy) can proliferate through an existing organ structure and the organism. In my mind, it also has the potential to better understand early development through the use of GFP mutants (CFP, YFP); though that is speculation on my part.
But I digress, sometimes my biology geek nature gets the best of me, the real reason I started this post was to nit-pick and complain once again over the sorry state of scientific literacy in the field of Journalism. In the article from the BBC, they make a mistake that even a freshman biology student would not make:
Because the pig’s genetic material is green, it is easy to spot.
Now, the pig’s “genetic material” is not green, it is the product of the genetic material, the protein.
Also, I do not think (though I could be wrong) that this part is correct:
So if, for instance, some of its stem cells are injected into another animal, scientists can track how they develop without the need for a biopsy or invasive test.
I don’t see how if stem cells were injected to repair a kidney or heart muscle how they would track their proliferation without some kind of invasive technique; the excitation wavelength and the resulting fluorescence would be blocked by the layers of the epidermis.
Discuss
1 This, at least, is how I have created stably-transfected mammalian cells with GFP-tagged proteins.
or they might have done pronuclear injection of DNA.
rik,
that is true, I searched for an hour on pubmed and could not find a paper on it. However, I just referred to my own professional experience on how they did it (I have talked to one researcher who thought about doing a similar experiment)
Do any of these green animals breed true?
After a few crosses they could. The GFP pheontype will be dominant.
After a few crosses they could. The GFP pheontype will be dominant.
So do we now have normally-breeding lines of green animals? I bet we could fund genetic research by selling them as pets!
I’ve got a question:
If these pigs glow in the dark. If all their tissues glow, what about their retinas? What about the inside of their eyeballs?
Are they able to see, especially in low light, without their own glow blinding them?
GFP does not glow green except in response to stimulation with UV light. Unless you want green pigs in the haunted house at DisneyLand, the green pig is just for show.
On the other hand, the use of animals having a mix of GFP expressing cells and non-expressing cells (produced in any one of a number of ways) is an extremely powerful way of marking cell lineages in a number of different organisms. Except for the most external of structures, e.g. skin, or the smallest, clear animals (e.g. nematodes, zebra fish, sometimes fly larvae), little information can be gathered about internal structures without dissection.
Thank you Mike.