Recently a paper was published in Science which reported that in human genome some codons, apart from coding amino acids, also serve as binding signals for certain proteins that control gene activity. Well, this is another instance of overlapping of the genetic code with yet another code (regulatory code, in this case). The funny thing is that both the press release and the news outlets are writing that “scientists have discovered a second code hiding within DNA”. Yes, Edward, a second code… Well, the sixth second code, to be exact 🙂

The following excerpt from the 2011 paper by Edward Trifonov makes it clear:

According to the media sympathetic to science and enthusiastic about sensational discoveries, the “Second Genetic Code” as it was called by New York Times was discovered by Ya-Ming Hou and Paul Schimmel and published in Nature in 1988. It was about recognition of tRNAs by respective aminoacyl-tRNA synthetases. Thirteen years later New Scientist announced the second Second Genetic Code, discovered by Jenuwein and Allis and published in Science. This time it was about histone modifications. Five years later, New York Times, again, reported about “a second code in DNA in addition to the genetic code”. This was already the third Second Genetic Code, discovered by Segal et al, suggesting now nucleosome positioning rules. One, surely, would raise eyebrows having learned that there is also the fourth Second Genetic Code — on interaction specificities between proteins and DNA, and the fifth Second Genetic Code, the name given by Nature magazine to the set of rules governing gene splicing. Bewildered reader, naturally, would say “I’m done with seconds, can I have a third?”