Xref: utzoo sci.bio:1329 sci.astro:2378 sci.philosophy.tech:675 Path: utzoo!utgpu!water!watmath!clyde!att!ucbvax!husc6!bloom-beacon!athena.mit.edu!ayermish From: ayermish@athena.mit.edu (Aimee Yermish) Newsgroups: sci.bio,sci.astro,sci.philosophy.tech Subject: Re: DNA for interstellar messages Summary: oh, come on... Keywords: realities of viruses Message-ID: <6211@bloom-beacon.MIT.EDU> Date: 14 Jul 88 23:57:29 GMT References: <2743@bath63.ux63.bath.ac.uk> <2244@ur-tut.UUCP> <3916@ut-emx.UUCP> Sender: daemon@bloom-beacon.MIT.EDU Reply-To: ayermish@athena.mit.edu (Aimee Yermish) Organization: Massachusetts Institute of Technology Lines: 44 Besides the problems of not wanting to let loose a nasty evil killer phage from hell on the nice friendly space aliens, there are some realities that just don't make walkie-talkie-viruses the most promising of methods. 1. Why would you *want* to use DNA, which is not a particularly obvious code, for communication with another planet? Sagan squares seem a lot more promising. Remember that viruses are generally pretty small and it's all they can do to contain their *own* coding information, so huge quantities of interesting stuff are probably out of the question. 2. You're assuming that there are cells on the receiving planet that can (a) be infected by the virus (tailspikes are pretty specific enzymes, y'know) (b) replicate it (requires the presence of machinery which can transcribe and translate the code, not to mention the correct precursors) and (c) lyse it (probably the easiest step, if you've gotten that far, but it still requires a susceptibility to whatever protease the virus has). Somehow I don't think that's a terrific assumption to make. 3. Unless you stuck the virus in some nice container, space vacuum might well do nasty things to the virus. But if you're sending a nice container, why not put something more self-explanatory (like, say, a picture) in it? 4. Why send a single probe that moves slower than light and gets stuck on asteroids and falls into stars and such when you can send a electromagnetic radiation-type message? 5. Speaking of electromagnetic radiation, there's an awful lot of it out there in space with no atmosphere to protect you. UV radiation does bad things to DNA. In particular, it dimerizes adjacent thymidine residues, leaving you with something unreadable. Here on earth, the cells have evolved all sorts of complex mechanisms to find and correct errors. Viruses don't carry those mechanisms with them. I'd think of some more, but I have to run. Sorry to burst bubbles. --Aimee ------------------------------------------------------------------ Aimee Yermish ayermish@athena.mit.edu MIT couldn't care less about anything I say. (as long as I finish that last paper...)