bs_wab@ux63.bath.ac.uk (Bains) (07/01/88)
Around the end of my undergraduate career I remember reading a paper on the possibility of using DNA sequences for interstellar communication. The idea was that you launched your message into space as a virus, and it replicated itself wherever it landed. As only one virus needed to 'get through' to spread the message this meant that a few tonnes of virus could be as effective as gigawatts of maser beams. The authors searched the sequence of a gene from a bacteriophage (Phi-X-174 I think) for evidence for a message, (but fairly obviously found none: if they had, I would not need reminding of the details!) Or so the theory went. While full of rather substantial holes, it might be more reasonable when combined with recent discoveries of 'catalytic RNA', and I would like to track down the paper to follow this up. It was published before summer 1979, and I think in ICARUS. Has anyone a) come across this paper before or b) come across similar ideas anywhere else? Many thanks for your help. William Bains Department of Biochemsitry University of Bath Claverton Down Bath BA2 7AY UK
ralf@b.gp.cs.cmu.edu (Ralf Brown) (07/03/88)
In article <2743@bath63.ux63.bath.ac.uk> bs_wab@ux63.bath.ac.uk (Bains) writes: }Around the end of my undergraduate career I remember reading a paper }on the possibility of using DNA sequences for interstellar communication. }Has anyone a) come across this paper before or b) come across similar }ideas anywhere else? I remember reading (circa 1981/82) about a virus whose DNA had a sequence which coded for THREE different proteins, depending on whether one started reading at base N, base N+1, or base N+2. (there are three bases per amino acid of the protein). One of the suggested explanations was that it might be just such a message, as it was considered unlikely for such a DNA sequence to evolve by itself. -- {harvard,uunet,ucbvax}!b.gp.cs.cmu.edu!ralf -=-=- AT&T: (412)268-3053 (school) ARPA: RALF@B.GP.CS.CMU.EDU |"Tolerance means excusing the mistakes others make. FIDO: Ralf Brown at 129/31 | Tact means not noticing them." --Arthur Schnitzler BITnet: RALF%B.GP.CS.CMU.EDU@CMUCCVMA -=-=- DISCLAIMER? I claimed something?
bilbo@pnet02.cts.com (Bill Daggett) (07/04/88)
bs_wab@ux63.bath.ac.uk (Bains) writes: >Around the end of my undergraduate career I remember reading a paper >on the possibility of using DNA sequences for interstellar communication. >The idea was that you launched your message into space as a virus, >and it replicated itself wherever it landed. As only one virus needed >to 'get through' to spread the message this meant that a few tonnes of >virus could be as effective as gigawatts of maser beams. The authors >searched the sequence of a gene from a bacteriophage (Phi-X-174 I >think) for evidence for a message, (but fairly obviously found none: >if they had, I would not need reminding of the details!) Maybe it has worked... Maybe WE are the message! :-) Bill UUCP: {ihnp4!scgvaxd!cadovax rutgers!marque}!gryphon!pnet02!bilbo INET: bilbo@pnet02.cts.com * Sometimes The Dragon Wins! * Still looking for the best Amiga BBS software to resurrect Bilbo's Hideaway on - but not holding breath!
jwm@stdc.jhuapl.edu (Jim Meritt) (07/06/88)
In article <4719@gryphon.CTS.COM> bilbo@pnet02.cts.com (Bill Daggett) writes: }bs_wab@ux63.bath.ac.uk (Bains) writes: }>Around the end of my undergraduate career I remember reading a paper }>on the possibility of using DNA sequences for interstellar communication. } }Maybe it has worked... Maybe WE are the message! :-) So thinking of the spiritualists, the medium is the message? Disclaimer: Individuals have opinions, organizations have policy. Therefore, these opinions are mine and not any organizations! Q.E.D. jwm@aplvax.jhuapl.edu 128.244.65.5 (James W. Meritt)
powi@ur-tut (Peter Owings) (07/06/88)
In article <2743@bath63.ux63.bath.ac.uk> bs_wab@ux63.bath.ac.uk (Bains) writes: > >Has anyone a) come across this paper before or b) come across similar >ideas anywhere else? > Well, I haven't heard anything about this paper, but one scientist not far from you takes this kind of thing very seriously. I was fortunate enough to have several conversations with Sir Fred Hoyle when he visited the University of Rochester. If there is anyone who has written about stuff like "Bacteria From Space", Sir Fred has. You might try looking at a book called _Grains_to_Bacteria_. The only problem with this book is that it is very technical, going into spectral observations of interstellar particles. But, if you want someone who has put a lot of thought into this, I highly recommend Sir Fred. I don't think that he is still teaching at Cambridge, but he is still around there somewhere. Peter... >Many thanks for your help. > 's alright, >William Bains Peter Owings University of Rochester "The Cold and Distant Outpost, USA"
flash@ee.qmc.ac.uk (Flash Sheridan) (07/06/88)
In article <2244@ur-tut.UUCP> powi@tut.cc.rochester.edu.UUCP (Peter Owings) writes: >In article <2743@bath63.ux63.bath.ac.uk> bs_wab@ux63.bath.ac.uk (Bains) writes: >> > Well, I haven't heard anything about this paper, but one scientist >not far from you takes this kind of thing very seriously. I was fortunate >enough to have several conversations with Sir Fred Hoyle when he visited Remember, on this issue (_not_ astronomy) Hoyle is a crank. I'm not saying he's wrong, but he is a crank. I've heard him lecture on it; he misrepresents probability theory in order to show that evolution is impossible. From: flash@ee.qmc.ac.uk (Flash Sheridan) Reply-To: sheridan@nss.cs.ucl.ac.uk or_perhaps_Reply_to: flash@cs.qmc.ac.uk
bs_wab@ux63.bath.ac.uk (Bains) (07/06/88)
In article <2244@ur-tut.UUCP> powi@tut.cc.rochester.edu.UUCP (Peter Owings) writes: >> > ... I was fortunate >enough to have several conversations with Sir Fred Hoyle when he visited >the University of Rochester. If there is anyone who has written about >stuff like "Bacteria From Space", Sir Fred has. You might try looking at >a book called _Grains_to_Bacteria_. The only problem with this book is >that it is very technical, going into spectral observations of interstellar >particles. > Peter Owings > University of Rochester Ah, not quite what I had in mind because i) The interstallar grains that Hoyle was concerned about were meant to be the remains of entire organisms (if I understand Hoyle's ideas right, which I quite possibly do not), not of 'pure' message. If you use an entire organism as a messenger, then you have the problem of how to stop your message evolving into meaningless garbage. (The same problem attends the idea put forward in a previous posting (sorry, I don't have it in front of me) that such a message exists and 'we are that message'. Apart from anything else, which 'we'? There is about 1% genetic difference between different individuals, so which 'us' is the right message? But I digress.) ii) If Hoyle is right, and a substantial amount of interstellar dust is actually of biological origin, it would mean that our hypothetical communicators would have had to dismantle their entire solar system, maybe their entire globular cluster, just to send their message out. This seems a little entreme. iii) Hoyle's data are EXTREMELY shakey! His 'matching' between interstellar IR spectra and biological sample spectra are essentially 'fudge-it-till- it-fits' excercises, with different bacteria and protein molecules being added to his 'biological' sample until he got the right spectra. As with his advocacy of the 'steady state' theory, Hoyle's insistance in this hypothesis appears driven more by his dislike of creationists than by scientific rigour (if life is generated in outer space, then the chances that it arose spontaneously are much greater than if it has to arise on Earth, as there is much MORE space than Earth). His idea that the archeopteryx fossil is a fake has similar motivation, apparently (according to a dinosaur fanatic who has heard him speak ont eh subject).
ethan@ut-emx.UUCP (Ethan Tecumseh Vishniac) (07/06/88)
In article <2244@ur-tut.UUCP>, powi@ur-tut (Peter Owings) writes: > In article <2743@bath63.ux63.bath.ac.uk> bs_wab@ux63.bath.ac.uk (Bains) writes: ... A bunch of stuff about using DNA as a kind of replicating message carrier. > >Has anyone a) come across this paper before or b) come across similar > >ideas anywhere else? > > First, it seems to me that dropping a replicating bit of DNA into someone else's biosphere is indeed a message of sorts...like dropping a bomb on their house. Regardless of contents it is an extremely hostile act. > Well, I haven't heard anything about this paper, but one scientist > not far from you takes this kind of thing very seriously. I was fortunate > enough to have several conversations with Sir Fred Hoyle when he visited > the University of Rochester. If there is anyone who has written about > stuff like "Bacteria From Space", Sir Fred has. You might try looking at > a book called _Grains_to_Bacteria_. The only problem with this book is > that it is very technical, going into spectral observations of interstellar > particles. Hmm.... there is one other problem with the book. Almost all experts on the interstellar medium (actually all but Hoyle and Wickramsinghe) consider their interpretation of the spectral features to be ludicrous. It's not my field, but the criticisms I've heard sounded devastating. -- I'm not afraid of dying Ethan Vishniac, Dept of Astronomy, Univ. of Texas I just don't want to be {charm,ut-sally,ut-ngp,noao}!utastro!ethan there when it happens. (arpanet) ethan@astro.AS.UTEXAS.EDU - Woody Allen (bitnet) ethan%astro.as.utexas.edu@CUNYVM.CUNY.EDU
wooding@daisy.UUCP (Mike Wooding) (07/06/88)
In article <4719@gryphon.CTS.COM> bilbo@pnet02.cts.com (Bill Daggett) writes: }bs_wab@ux63.bath.ac.uk (Bains) writes: }>Around the end of my undergraduate career I remember reading a paper }>on the possibility of using DNA sequences for interstellar communication. } }Maybe it has worked... Maybe WE are the message! :-) Do you suppose "they" knew about error correcting codes? :-) m wooding
dlp@ih1ap.ATT.COM (Random @ rebmA) (07/06/88)
> > bs_wab@ux63.bath.ac.uk (Bains) writes: >>Around the end of my undergraduate career I remember reading a paper >>on the possibility of using DNA sequences for interstellar communication. You don't mention when this paper was written, but I recall a similar scenario. Check out 'The Andromeda Strain' then 'Mutant 59, The Plastic Eaters' by the same author (whos name escapes me). Random
watson@ames.arc.nasa.gov (John S. Watson) (07/07/88)
> Around the end of my undergduate career I remember reading a paper > on the possibility of using DNA sequences for interstellar communication. > The idea was that you launched your message into space as a virus, > and it replicated itself wherever it landed. This reminds me of the book CONTACT by Carl Sagen, where the scientist looks for a coded message from the creator(s) of the universe in the number PI, i.e: 3.1415...IFYOUCANREADTHISPHONEHOMEET...234328... I alway think of this whenever I see images of the Mandelbrot set and realize thoughs incredibly beautiful and complex pictures were made with iterations of the simple equation Xnew = Xold**2 + Constant (all complex numbers). Maybe our creator(s) stuck a message somewhere in our DNA, "Greetings", "may the Force be with you", "Have a Nice Day" or maybe a copywrite notices and patent numbers. :-) -- John "Metaman" Watson, IBM heir in hiding ARPA: watson@ames.arc.nasa.gov NASA Ames Research Center UUCP: ...!ames!watson Any opinions expressed herein are solely the responsibility of the author and do not represent the opinions of NASA or the U.S. Government, yet.
dalex@eleazar.dartmouth.edu (David Alexander) (07/07/88)
In article <1027@ih1ap.ATT.COM> dlp@ih1ap.ATT.COM (Random @ rebmA) writes: > Check out 'The Andromeda Strain' then 'Mutant 59, The Plastic > Eaters' by the same author (whos name escapes me). Michael Crichton. **************************************************************************** * Per lor maledizion si non si perde Dave Alexander * * Che non possa tornar l'etterno amore dalex@eleazar.dartmouth.edu * * Mentre che la speranza ha fior del verde *****************************
willner@cfa250.harvard.edu (Steve Willner P-316 x57123) (07/07/88)
From article <2244@ur-tut.UUCP>, by powi@ur-tut (Peter Owings): > I was fortunate enough to have several conversations with Sir Fred > Hoyle when he visited the University of Rochester. If there is > anyone who has written about stuff like "Bacteria From Space", Sir > Fred has. You might try looking at a book called > _Grains_to_Bacteria_. The only problem with this book is that it > is very technical, going into spectral observations of interstellar > particles. Sorry, but I doubt that's the only problem. (Some might say it's not a problem at all.) Though I haven't read this particular book, I am familiar with the Hoyle and Wickramasinghe papers published in journals. Although the observed interstellar spectra and the polysacccharide or "bacteria" spectra look superficially very similar, a closer look reveals that the disagreement is in the _wavelength_ axis. That is, the interstellar spectral features just do not have the wavelengths predicted by the Hoyle/Wickramasinghe model. While I would not consider a disagreement in the strengths of the various features a serious problem, the wavelengths are a different matter. Wavelengths ought to depend mainly on the kind of material producing the features, and a discrepancy in wavelength strongly suggests that the identification is wrong. Moreover, there are far more plausible identifications for most of the observed spectral features. -- Steve Willner Phone 617-495-7123 Bitnet: willner@cfa 60 Garden St. FTS: 830-7123 UUCP: willner@cfa Cambridge, MA 02138 USA Internet: willner@cfa.harvard.edu
dietz@gvax.cs.cornell.edu (Paul F. Dietz) (07/08/88)
From article <2244@ur-tut.UUCP>, by powi@ur-tut (Peter Owings): > I was fortunate enough to have several conversations with Sir Fred > Hoyle when he visited the University of Rochester. If there is > anyone who has written about stuff like "Bacteria From Space", Sir > Fred has. You might try looking at a book called > _Grains_to_Bacteria_. The only problem with this book is that it > is very technical, going into spectral observations of interstellar > particles. You might want to read Shapiro's (I believe that's the name) description of H&W's work in the book "Origins". The description of H&W's methodology is fascinating. They apparently took some organic spectra and ran them through a blurring procedure, then remarked at how the resulting spectra resembled that of interstellar grains. Shapiro gave an analogy to illustrate the validity of this procedure. Suppose you have a picture of a man taken on a foggy night. You claim this is actually a picture of President Reagan. To support your claim, you take a picture of Reagan and blur it, then note the similarities (for example, in both pictures the figures have two arms and two legs). Nature wised up after a while and stopped accepting their papers. Paul F. Dietz dietz@gvax.cs.cornell.edu
alaa@pedsga.UUCP (07/08/88)
I read about the subject in Sir Fred Hoyles book "The Intelligent Universe". Although I am no expert in the subject (or maybe because of that), the book seemed fascinating. However I should read some critique of the theories presented in it to be able to form my own opinion on the matter. In any case I recommend reading that book. As for the DNA messages, I think the messages were sent via microwave or lazer or some form of signals duplicating DNA codes. And not by sending an actual virus (friendly earthlings would'nt do a thing like that, would they? I mean they have not confirmed that there is some one there to harrass yet :-; ) --Alaa ...!petsd!pedsgd!alaa
sam@murdu.OZ (Sam Ganesan) (07/08/88)
In article <1027@ih1ap.ATT.COM> dlp@ih1ap.ATT.COM (Random @ rebmA) writes: >> >> bs_wab@ux63.bath.ac.uk (Bains) writes: >>>Around the end of my undergraduate career I remember reading a paper >>>on the possibility of using DNA sequences for interstellar communication. >You don't mention when this paper was written, but I recall a similar >scenario. Check out 'The Andromeda Strain' then 'Mutant 59, The Plastic >Eaters' by the same author (whos name escapes me). The author, I am pretty sure is Michael Crichton. Sam Ganesan ****************************************************************************** E - mail : ACSnet: sam@murdu.mu.oz JANET: sam%murdu.mu.oz@uk.ac.ukc ARPA : sam%murdu.mu.oz.au@uunet.uu.net sam%murdu.mu.oz@uk.ac.ean-relay UUCP : {uunet,pyramid,mcvax,nttlab}!munnari!murdu.mu.oz.au!sam Snail : Sam Ganesan, Microbiology Dept,Melbourne University, Parkville, Victoria 3052, Australia. ******************************************************************************
dlp@ih1ap.ATT.COM (David Lee Pope @ rebmA) (07/08/88)
I couldn't resist! This is by far the most creative misspelling I have ever seen. :^) Random
bilbo@pnet02.cts.com (Bill Daggett) (07/10/88)
bs_wab@ux63.bath.ac.uk (Bains) writes: >i) The interstallar grains that Hoyle was concerned about were meant to be >the remains of entire organisms (if I understand Hoyle's ideas right, >which I quite possibly do not), not of 'pure' message. If you use an entire >organism as a messenger, then you have the problem of how to stop your >message evolving into meaningless garbage. (The same problem attends the >idea put forward in a previous posting (sorry, I don't have it in front >of me) that such a message exists and 'we are that message'. Apart from >anything else, which 'we'? There is about 1% genetic difference between >different individuals, so which 'us' is the right message? But I digress.) Nothing is perfect. I mean some message is better then no message and so far we have no message. The DNA transmitter may not be "intelligent" and it would include ALL life and not just some "special" sentient creature dreaming of a way to communicate with anther planet. The point is you do not stop the message from evolving into menaingless garbage. Meaningless garbage is exactly what has created us for 5 billion years (or so). If it is TRUE, does the human species resemble the original DNA message transported through time and space from so many distant places? This is what I meant by WE (may be) are the message. It can't be whole. As far as how a planet would transmit all its DNA stuff through space perhaps when its star dies and novas the explosion rather then consuming the third planet from the sun would break it up and spew it out into the cosmos to land a tiny portion someday on another planet? This was never the way I thought of communicating with other life in the universe. It sort of ruins Star Trek. Bill UUCP: {ihnp4!scgvaxd!cadovax rutgers!marque}!gryphon!pnet02!bilbo INET: bilbo@pnet02.cts.com * Sometimes The Dragon Wins! * Still looking for the best Amiga BBS software to resurrect Bilbo's Hideaway on - but not holding breath!
king@client2.DRETOR.UUCP (Stephen King) (07/12/88)
In article <1027@ih1ap.ATT.COM> dlp@ih1ap.ATT.COM (Random @ rebmA) writes: >You don't mention when this paper was written, but I recall a similar >scenario. Check out 'The Andromeda Strain' then 'Mutant 59, The Plastic >Eaters' by the same author (whos name escapes me). _The Andromeda Strain_ was written by Michael Crichton. _Mutant 59, The Plastic Eater_ (one of my favourite novels) was co-authored by Kit Pedlar and Gerry Davis, known for the BBC series _Doomwatch_. ---Methinks the facts escape you---forgive spelling mistakes---SJ King---
al@gtx.com (Alan Filipski) (07/13/88)
In article <1410@murdu.OZ> sam@murdu.UUCP (Sam Ganesan) writes: ->In article <1027@ih1ap.ATT.COM> dlp@ih1ap.ATT.COM (Random @ rebmA) writes: ->>> ->>> bs_wab@ux63.bath.ac.uk (Bains) writes: ->>>>Around the end of my undergraduate career I remember reading a paper ->>>>on the possibility of using DNA sequences for interstellar communication. ->>You don't mention when this paper was written, but I recall a similar ->>scenario. Check out 'The Andromeda Strain' then 'Mutant 59, The Plastic ->>Eaters' by the same author (whos name escapes me). -> ->The author, I am pretty sure is Michael Crichton. -> In a similar vein, I remember reading a short story in which Earth was doomed by some imminent catastrophe, so a project called the "Great Space Fuck" was created to launch Earthian (Terran? Gaian? what's the word?) genetic material to some plausible nearby planetary system. The title of the story may have been "The Great Space Fuck", but I am certain the phrase was used in the story. It must have been in the 1960's, and I believe it was a famous author. I probably still have the book that contains the story, but I don't feel like grepping through about 10 shelf-feet of dusty, crumbling paperbacks to find it. Anyone remember this? It's probably about time to remove this from sci.bio ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ( Alan Filipski, GTX Corp, 8836 N. 23rd Avenue, Phoenix, Arizona 85021, USA ) ( {allegra,decvax,hplabs,amdahl,nsc}!sun!sunburn!gtx!al (602)870-1696 ) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ayermish@athena.mit.edu (Aimee Yermish) (07/15/88)
Actually, it's pretty common for DNA (especially viral DNA) to have coding sequences which overlap or can be spliced together in different patterns. Bear in mind that not every single amino acid in a given protein is necessary for its folding or its function, and that, in fact, many proteins have chunks taken out of them after they are synthesized. Quite a few organisms use overlapping sequences to regulate the relative amounts of various proteins. As to why, well, if you're a cell, it's a slight advantage to have less DNA, because it doesn't take so long or so much effort to replicate. If you're a virus, you're under a serious constraint: the size of the capsid that will hold the genome. There are some really clever tricks some of those bugs have managed. One I recall offhand is a phage that relies on a frameshift error in translation (a rather uncommon event) to produce very small amounts of lysis protein (what pops the cell open and lets all the progeny phage free) in relationship to the amount of coat protein. In other words, it makes lots of coat protein (and hence lots of progeny phage) and a very little lysis protein (a little dab'll do ya, and you don't want to killl the cell before you're good and ready), all without the messy waste of regulatory proteins and sequences. Very elegant... --Aimee ------------------------------------------------------------------ Aimee Yermish ayermish@athena.mit.edu MIT couldn't care less about anything I say. (as long as I finish that last paper...)
ayermish@athena.mit.edu (Aimee Yermish) (07/15/88)
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...)
bs_wab@ux63.bath.ac.uk (Bains) (07/26/88)
In article <6211@bloom-beacon.MIT.EDU> ayermish@athena.mit.edu (Aimee Yermish) writes: >1. Why would you *want* to use DNA, which is not a particularly >obvious code, for communication with another planet? That is one question I was hoping the original article might answer, but for starters, see 5 below. >2. You're assuming that there are cells on the receiving planet that >can (a) be infected by the virus ... and it can replicate and lyse. No I am not. i) The ORIGINAL PAPER was talking about viruses, which is why I thought it dodgy. ii) Not all viruses enter cells by such specific mechanisms as the well-known bacteriophages: a membrane fusion mechanism could be much more general. iii) I was not all that interested in viruses themselves anyway, but in viroids, which appear to be self-replicating RNAs requiring only RNA precursors to reproduce. The RNA strand is both message and polymerase. So no host enzymes required. Actually, no host cell lysis required either as the cell either dies from the metabolic effort of carrying all those viroids around (which is apparently what happens to plant cells) or does not, in which case it passes the viroid on vertically. > >3. .., space vacuum >might well do nasty things to the virus. ... but not to a viroid, which is a single chemical. (Not necessarily to a virus either, in fact, as the ATCC can provide many of them freeze-dried with 'keep cold' on the side.) >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? ... because ... >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. ... and to em signals too. The power required to send a recogniseable electromagnetic signal half way across the galaxy is fantastic, and you still run the risk that the receiver will not be listening at the right time or on the right frequency. Both would be no problems to self-propagating RNA. The radiation damage to the chemical is a major problem, however. Whether it is less of a problem depends critically on how much material you launch, how much is needed on landing, interstellar UV and X-ray intensities and radiation-sensitivity of your molecule. As this was a 'hey, has anyone heard of this' search for a previously published paper, I have not worked these points out! But you have hit a serious nail on the head with this one. > >I'd think of some more, but I have to run. Sorry to burst bubbles. > No problem. The regular sound of bursting bubbles is what distinguishes science from pseudoscience. >Aimee Yermish ayermish@athena.mit.edu William Bains: wbains@bionet-20.arpa, bs_wab@uk.ac.bath.ux63
eddy@boulder.Colorado.EDU (Sean Eddy) (07/28/88)
In article <2863@bath63.ux63.bath.ac.uk> bs_wab@ux63.bath.ac.uk (Bains) writes: >iii) I was not all that interested in viruses themselves anyway, but in >viroids, which appear to be self-replicating RNAs requiring only >RNA precursors to reproduce. The RNA strand is both message and polymerase. This is (unfortunately for the romantics of the "RNA world" hypothesis) not correct. The replicase involved in viroid replication has not been identified, to my knowledge. The known RNA catalytic activity of viroid RNAs is limited to self-cleavage and such. (Unless you know of something quite recent -- but here in the land of Tom Cech, such a discovery would have left the place in chaos...) The only RNA-based "polymerase" in the literature so far is a derivative of the _Tetrahymena_ self-splicing group I intron, which is capable of rearranging ribooligonucleotides to a small extent to make both longer and shorter products. - Sean Eddy - Molecular/Cellular/Developmental Biology; U. of Colorado at Boulder - eddy@boulder.colorado.EDU !{hao,nbires}!boulder!eddy - - "But the scientist is intensely religious -- he is so religious - that he will not accept quarter-truths, because they are an - insult to his faith." - - Sinclair Lewis, in _Arrowsmith_