Two new nucleotides have been added to the standard four DNA code signals. These were found in epigenetic research looking at how methylation of DNA modifies gene expession. This doesn't change the coding of protein itself. Epigenetics is the hot new field that is adding to our knowledge of the complexity of DNA functions. http://www.sciencedaily.com/releases/2009/04/090416144639.htm - In another hot area of research on extremophiles, bacteria in very strange places, bacteria have been found with no oxygen available. Life is very adaptable. http://sciencenow.sciencemag.org/cgi/content/full/2009/416/2