Orgel, Leslie

Orgel, Leslie E. The Origin of Life on the Earth. Scientific American (October 1994) 11-S3. 

O Brien, Paul ix O Brien, Steve 15 Orgel, Leslie 9,13, Owston, P.G. 11... 

The problem in its entirety can be characterised by means of analogies. Thus the chemist Leslie Orgel, who carried out successful experiments on chemical evolution for many years, compared the struggle to solve the biogenesis problem with a crime novel the researchers are the detectives looking for clues to solve the case . But there are hardly any clues left, since no relicts remain from processes which took place on Earth more than four billion years ago. 

In another study of the problem of the prebiotic adenine synthesis, Leslie Orgel concludes that, in spite of many uncertainties, the formation of these complex heterocyclic bases probably required three preconditions ... 

Leslie Orgel and co-workers took up this problem and studied the non-enzymatic polymerisation of mononucleotides, i.e., the question as to whether single nucleic acid building blocks can undergo polycondensation on a corresponding complementary matrix. The substrates used were the 5 -phosphoimidazolides of adenosine (ImpA) and guanosine (ImpG), the matrices poly(U) and poly(C). 

The RNA world has its critics as well as its proponents. A third group is formed by the soft critics , who warn of too much optimism one of these is Leslie Orgel, an expert on the problems involved, who made it quite clear that the RNA world is a hypothesis and nothing more. 

A majority of biogenesis researchers seem to accept the RNA world, in spite of the many unanswered questions a world in which protein synthesis, coded by nucleic acids and catalysed by ribosomes, did not yet occur. Leslie Orgel, probably the most profound connoisseur of this difficult metier, calls attention to important consequences which follow from acceptance of the RNA world. In summary, Orgel discusses two possibilities ... 

Whether the polymers shown schematically in Fig. 6.21 (or similar forms) were ever of importance on the Earth as information carriers is an open question. Leslie Orgel considers the alanyl nucleotides synthesized by Diederichsen to be possible and suitable candidates for a pre-RNA world (Orgel, 2003). 

Finally, an observation on Wachtershauser made by R. Shapiro in his book Planetary Dreams, he recounts Leslie Orgel s judgement on Wachtershauser s ideas, ... that he1 considered the work to be the most important finding in the last century (Shapiro, 1999). The Science journalist M. Hagmann (Zurich, Switzerland) has provided a comprehensive profile of Wachtershauser (Hagmann, 2002). 

In 1998, about three years after the Lazcano/Miller publication appeared, Leslie Orgel published the article which we have already mentioned above. He subjected their ideas to a critical examination and came to the rather pessimistic conclusion that some of their speculations were much too bold. 

This year has sadly seen the deaths of two of the pioneers of research on the origin of life Stanley L. Miller and Leslie Orgel. They provided us with vital insights and advances, and they will be greatly missed. Their approach to scientific research should serve as a model for the coming generation. 

The unveiling of the structural and functional complexity of RNA led Carl Woese, Francis Crick, and Leslie Orgel to propose in the 1960s that this macromolecule might serve as both information carrier and catalyst. The discoveiy of catalytic RNAs took this proposal from... 

Carl Woese Francis Crick Leslie Orgel... 

This at once raises the question Could RNA ever have arisen without the help of enzymes, without replicases Experiments by Leslie Orgel and his co-workers12 suggest that this was possible. It was found that zinc ions, found today as cofactors in all replicases, are excellent catalysts for the 3 -5 union of nucleotides, thus allowing the template-instructed synthesis of polymers. This was first demonstrated with poly-C as template. If activated G and A nucleotides are offered, in equal concentration, then G is preferentially incorporated into the product by a factor, depending on reaction conditions, between 30 and 200. 

Acknowledgements. I am very grateful to Dr. Leslie E. Orgel, F.R.S., for most helpful comments on the manuscript, and to Dr. Claus E. Schaffer, Chemistry Department I, University of Copenhagen, for very valuable discussions. 

When considering whether aliens would try to seed other planets with life, Francis Crick and Leslie Orgel wrote ... 

Francis Crick also thinks that life on earth may have begun when aliens from another planet sent a rocket ship containing spores to seed the earth. This is no idle thought Crick first proposed it with chemist Leslie Orgel in 1973 in an article entitled Directed Panspermia in a professional science journal called Icarus. A decade later Crick wrote a book, Life Itself, reiterating the theory in a 1992 interview in Scientific American on the eve of the publication of his latest book, Crick reaffirmed that he thinks the theory is reasonable. 

Although the reviewers listed above have provided many constructive comments and suggestions, they were not asked to endorse the conclusions or recommendations, nor did they see the final draft of the report before its release. The review of this report was overseen by Leslie Orgel, Salk Institute for Biological Studies. Appointed by the National Research Council, he was responsible for making certain that an independent examination of this report was carried out in accordance with institutional procedures and that all review comments were carefully considered. Responsibility for the final content of this report rests entirely with the authoring committee and the institution. 

Figure 2-43. Helical staircase with changing handedness from Oigel (reproduced with permission from Leslie L. Orgel, Ja Jolla, California) [65],...

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