Science - Genetic Code Sees Double

[Monique]

Interesting, never trust a dogma.


Genetic Code Supports Targeted Insertion of Two Amino Acids by One Codon

"Call it the genetic version of a double-entendre. Scientific dogma dictates that various three-letter combinations of our genetic sequence each "mean" exactly one thing--each codes for a particular amino acid, the building block of proteins. But a protozoan named Euplotes crassus appears to be more versatile: One of its three-letter combinations has two meanings, coding for two different amino acids. Although the find may seem trivial, it poses a major challenge to more than 4 decades of scientific thinking.
[..]
It's sort of like a warning shot not to get too comfortable with what we think is going on."
http://sciencenow.sciencemag.org/cgi/content/full/2009/108/3?etoc

 

[Q_Goest]

Hi Monique,
Sounds like a paradigm change of some sort, but unfortunately I can't quite grasp this. I understand that a portion of genetic code is being translated into proteins in two different ways, but not sure. I guess this set of DNA is translated into an mRNA, and from there it goes to the Ribosome but somehow those instructions are translated in 2 different ways?

And what's this about the 3' untranslated region? What does 3' mean?

Sorry, but this isn't my forte, though I'd be interested in understanding it better. Can you translate this into dummy speak?

(PS: I have access to the journal and looked at the original article but I can't make heads or tails)

 

[Andy Resnick]

Oh yeah- selenocysteine! UGA is also a stop codon, not a codon for cysteine. Strange it would make Science- I thought the amino acid was discovered about 20 years ago.

I think selenocysteine is present in mammalian cells as well, we've spent some time disucssing if we need to add selenium as an essential mineral to our cell cultures.

http://en.wikipedia.org/wiki/Selenocysteine