DNA ComputingOverviewDNADNA/CPU ComparisonLeonard M. AdlemanProof of Concept ExperimentProgramming the DNARecipeLigasesPolymeraseGel ElectrophoresisChecking CitiesDid it work?DrawbacksThoughtsSummaryReferencesDNA ComputingHerman G. Meyer IIISept. 28, 2004Overview•DNA•DNA/CPU Comparison•Leonard M. Adleman•Proof of Concept ExperimentDNA•Adenine, Thymine, Guanine, & Cytosine (A,T,C,G)•Polymerase•Watson-Crick Pairing (A-T,C-G)•Cheap•Compact Data Storage–1 cm^3 DNA = 10^12 CDs•RedundantDNA/CPU Comparison•CPU–Sequential Operations–addition, bit-shifting, logical operations (AND, OR, NOT, NOR)•DNA–Parallel Operations–Cut, Copy, Paste, RepairLeonard M. Adleman•Background in Mathematics & Computer Science•HIV Research•DNA/Turing Machine similar•Proof of ConceptProof of Concept Experiment•Directed Hamiltonian Path•Pseudo code–Generate random paths–For each path•Check Start/End points•Check Length•Check that all vertices exist–If any path passes all tests, HP existsProgramming the DNA•Cities•FlightsRecipe•In a test tube add–10^14 molecules of each city–10^14 molecules of each flight–Water, ligase, salt•Answer generated in about one second•100 trillion molecules representing wrong answers also generatedLigases•Bind molecules together•Concatenates DNA strandsPolymerase•Copies DNA•Primers (Start, Complement of End)•PCRGel Electrophoresis•Sort molecules by length•Molecules have a charge•Magnets usedChecking Cities•Attach city complement to iron ball•Suspend ball in solution•Watson-Crick pairing attraction•Wrong answers poured out•Repeat for each cityDid it work?•DNA remaining in test tube encoded the valid Hamiltonian PathDrawbacks•The process required much human intervention•Automation would be required for a “real” computer•Same method on 200 cities would require more than DNA than the mass of EarthThoughts•Could a DNA Computer get sick?–Virus–Cancer•Is it biodegradable?•Could a virus spread from computer to humans?•If so, could virus writers spread more deadly viruses? •New level of bioterrorismSummary•DNA can be used for simple calculations•DNA is a compact form of data storage•DNA is exponentially parallel•DNA is redundantReferences•Ars Technica. http://arstechnica.com/reviews/2q00/dna/dna-5.html•Scientific American - August 1998. pp 54-61•Science - Vol. 266. Nov. 11, 1994. pp
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