Meeting notice: The 99.10.5 meeting will be held at 7:30 p.m. at the Royal East (782 Main St., Cambridge), a block down from the corner of Main St. and Mass Ave. If you're new and can't recognize us, ask the manager. He'll probably know where we are. <><><><><><><><><><><><><><><><><><> Suggested topic: Roads to NT: Time to declare a winner? In 1986 Drexler outlined a couple of different paths to NT, defined as the construction of a general-purpose self- replicating programmable molecular assembler. (There are of course other definitions.) One development arc ran through an ever more capable biotechnology; another, through building an assembler ab novo, first by using smart molecular CAD/CAM systems, and then making and assembling the parts with synthetic chemistry or some pick-and- place system built out of arrays of STM tips or both. While both these development strategies have the same end, they differ in mode and tempo. The biotech route was imagined as snaking through hundreds of thousands of different projects, each with its own near-term goal, almost none of which would be primarily focussed on assemblers. The theory was that assemblers would just emerge out the steady stream of improvements developed to deal with a constantly expanding universe of applications. By contrast, the ab novo strategy would look much like a single coherent research project, one in which people were thinking about assemblers as such right from the start. The ab novo strategy had the advantage of illustrating and dramatizing the concept unambiguously, and perhaps for that reason most of the conversation about NT, with its interest in pushing atoms around on surfaces or building up designs for graspers and rod logic, seems to assume that as the preferred path of development. However it is perhaps time to come to terms with the fact that over the last 10 years or so the biotech strategy has opened what looks like an immense lead over ab novo in the assembler races. In more detail, the assemblers-through-biotech agenda runs as follows: Phase I: transplanting naturally evolved genes among nonconspecific organisms; II: developing new genes (i.e., coding the nucleotides directly); and III: rebuilding the biological cell so as to support a steadily larger repetoire of reactions and elements. Dig a bit into III, the theory goes, and before you know it you have an assembler sufficiently general-purpose for victory to be declared. While certainly full of question marks, this is a relatively clear road map, especially as compared to any available for ab novo, which has as yet no good, or even bad, idea of what an assembler will look like or how it will be built. The progress of biotech as measured against this map seems quite impressive. Phase I, with perhaps 10,000 plant biotech development projects (some estimates run much higher than that) now underway, is expanding dramatically in several sectors (food, research, drugs, specialty materials, and even information technology: using biological organisms as environmental monitors). Further, a number of research projects are buzzing into phases II and III above. While noone is using the equivalent of an assembly language for sequences as yet (though rational drug design is not far off), genes are now routinely made by stitching together bits of sequences taken from many different genes (taken in turn from many different species) via artificial recombination. [Nature v.391, n.6664, (1998): 288-291; Proceedings of the National Academy of Sciences of the United States of America, v.94, n.9, (1997): 4504-4509.] This is clearly Phase II work. Another example is inducing mutagenesis, transplanting the mutants into host organisms, filtering the host population for an improvement in the desired property, growing a new population out of the best of the breed, introducing yet another cycle of mutations, and so on. (http://www.che.caltech.edu/groups/fha/Enzyme/directed.html) There seem to be fewer Phase III projects, but the work on improving the control and computational capacities of cells now underway in Tom Knight's Microbial Engineering Lab (http://www.ai.mit.edu/people/tk/tk.html) qualifies. (See also Ralph Merkle's "Biotechnology as a route to nanotechnology" at http://www.merkle.com/papers/bionano.html.) The ab novo track crosses many interesting subjects, and there is every reason to continue to keep an interest in it. However to the degree that one is focussed on the issue of assembler development, it may be a waste of time to pay attention to much outside of biotech. Biotech is cheap, the pool of expertise and investment is growing rapidly, the number of potential applications is very large, work is underway in many jurisdictions, and the tools at hand for distributing information as it emerges could hardly be more powerful. It may bring us to the doors of NT long before those of us trained to think in terms of an ab novo assembler project have been expecting it. -- Fred Hapgood <><><><><><><><><><><><><><><><><><> Announcement Archive: http://world.std.com/~fhapgood/nsgpage.html. <><><><><><><><><><><><><><><><><><> If you wish to subscribe to this list (perhaps having received a sample via a forward) send the string 'subscribe nsg' to majordomo@world.std.com. Unsubs follow the same model. Discussion should be sent to nsg-d@world.std.com to which you need to subscribe separately. Note: you must be subscribed to nsg-d to post to it and you must post from the address from which you subscribed. (An anti- spam thing.) 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