10-28-2016, 12:00 AM
I haven't had time to check, but is it not also possible that a DNA analogue could be used - one with the same basic structure but different bases chosen from the many available? There are many purines and pyrimidines, after all.
Or, another possibility: AFAIK the genetic code is completely arbitrary; is it possible that alien life uses DNA with the same bases as ours but a different coding scheme?
And finally, I much doubt that the amino acids we use are the only ones suitable for use in proteins. In fact, there are quite a lot of Earthly proteins that incorporate amino acids there is no code for - they are converted after they go into the protein. The best example is hydroxyproline, used in colossal amounts (it's one of the major components of collagen) but with no DNA code for it at the moment.
Or, another possibility: AFAIK the genetic code is completely arbitrary; is it possible that alien life uses DNA with the same bases as ours but a different coding scheme?
And finally, I much doubt that the amino acids we use are the only ones suitable for use in proteins. In fact, there are quite a lot of Earthly proteins that incorporate amino acids there is no code for - they are converted after they go into the protein. The best example is hydroxyproline, used in colossal amounts (it's one of the major components of collagen) but with no DNA code for it at the moment.