Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!linus!decvax!cca!g-rh From: g-rh@cca.UUCP (Richard Harter) Newsgroups: net.misc Subject: Paper on abiogenesis Message-ID: <6652@cca.UUCP> Date: Mon, 6-Feb-84 13:26:01 EST Article-I.D.: cca.6652 Posted: Mon Feb 6 13:26:01 1984 Date-Received: Thu, 9-Feb-84 04:38:56 EST Lines: 62 Recently Paul Dubuc ran a transcription of a paper purporting to show that abiogenesis was an untenable concept. More recently he noted that no one had refuted it. Per his request, I will attempt to state what is wrong with the paper. Unfortunately, I did not save a copy of the paper, so I am relying on recall. Also I am not a biochemist and do not have the relevant reference material at hand, so there will be some lack of precision in my comments. The paper divides into two parts. In the first part it is argued that (a) proteins could not have formed spontaneously out of water (i.e. on the land or in the air), (b) that in liquid water they would disassociate, and (c) that they could not form in the presence of solid or gaseous water. In the second part, it is argued that the fact that all proteins are L proteins is highly improbable if proteins originally formed as a matter of chance. Amino acids come in two forms, right (D for dextro), and left (L for levro). The proteins occurring in life are made of either all L amino acids or all D acids. D type proteins are very rare. Let us dispose of the second argument first. It is a fact of biochemistry that the only way proteins can occur is either all L or all D. I do not recall off hand the reason -- it may be because that is the only way the amino acids will fit together or it may be a consequence of the mode of construction. In any case the calculations presented are irrelevant because they are based on a false assumption. The interesting question, which is not discussed, is why life is left handed rather than a mixture of left and right handed. There are two possibilities: (a) all life is descended from a single left-handed ancestor, or (b) there is some subtle reason why left handed forms are preferred. The first argument was not clear to me. I am not aware of any serious proposal that ice or steam played any part in the formation of life, so I can't judge whether the author was introducing a red herring or whether he was quoting something out of context. If he was referring to a real proposal, then I feel sure that he was misrepresenting the proposal -- the points he raised were obvious ones that any such proposal would have had to dealt with. His general point that proteins disassociate is well taken. In the absence of life organic molecules would build up in water, but they would also break down. The equilibrium point is well below the level of complexity required for life. There are some concentration mechanisms that have been pro- posed; however I am not qualified to evaluate them. Incidentally, the paper fusses about the notion that primitive Earth might have had a reducing atmosphere. As Haldane pointed out in the 20's, the oxygen in the atmosphere is produced by and maintained by plant life. Without life the atmosphere would either be reducing or neutral, depending on whether there were significant amounts of methane present. (The whole matter is currently under debate in the literature.) In short: this paper has a number of errors of logic. It has other flaws; quoted statements are misrepresented. Finally: I am not familiar with Coppredge. If this paper is a good example of the reasoning that Coppredge (sp?) uses, then Coppredge is not worth discussing. may be a consequence of the w