Vladimir I. shCherbak of al-Farabi University of Kazakhstan (located here) and Maxim A. Makukov of the Fesenkov Astrophysical Institute have suggested that DNA might have been sent to earth by aliens with a message hidden in the code.  They published their research in the journal Icarus.  They believe that the aliens ceded the earth (and perhaps the galaxy) with DNA knowing that it would lead to intelligent life and left the "hidden  code" for us to find once we evolved.