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Digital DNA Circuits
TheSync writes "ScienceNews has a story about digital DNA circuits. The circuits use proteins that activate or deactivate genes on the DNA for control. Since an inverter and an AND gate have been created, any digital logic circuit can now be done in DNA. Moreover, evolution can help make circuit elements work better. There is even a "databook" of BioBricks circuit elements and BioSPICE for biocircuit simulation."
But proteins go into a little 3D bag, while transistors need to be packed near a flat surface with current VLSI technologies.
Even your body doesn't rely upon chemical reactions to accurately predict certain outcomes. Studies have shown that nerve fibers in your arm will often send a "the ball is coming" signal to your brain well in advance of the actual signal reaching your fingers. This sort of predicative function makes complex tasks like walking and talking much easier, but when it catches up to you (like when you fall on the bottom step of a flight of stairs because you forgot how many steps there were) you crash and burn.
The point is, that chemical reactions are very slow. If they were faster, your brain (and your neurons in your arm) wouldn't have to guess. Because they're so slow they'd be very poor at brute force attacks, regardless of the sheer number of cells.
So, yes, you're dreaming.
The most interesting thing about this announcement is that this guy has been able to use evolution to improve his circuits. I don't expect molecular computers to surpass electronic computers, at least right away -- although they could theoretically perform faster than electronic computers in the short term, any advantage is offset by the time needed to convert the information to human-readable form (by finding and correctly reading the DNA sequence). As the article says, it's better to take advantage of the fact that you can "work with" bacteria. But if DNA computers could repair and upgrade themselves, they would have an advantage that electronics currently does not have. Electronics already is under intense artifical selection, and it can reproduce itself after a fashion, but unlike copper and aluminum, DNA computers can be randomly mutated, and the close homology between computers ensures that some of those mutations will be beneficial.
Reports of this sort have been coming out for a few years now - basically, all they are doing is a controlled induction of a promoter. It's nothing amazing. Chaining one promoter to express another promoter ad infinitum (or to restrict expression) is already done in nature and used extensively to create transgenic cell lines, bacteria, etc. Hell, they've already developed means to do basic computations with DNA that are more applicable/advanced then this in some respects.
I was listening to NPR the other day which focused on DNA as a computer.
The guy interviewed correllated the DNA genetic map to spaghetti code, a programmers worst nightmare. Apparently all through the genetic make-up of our bodies are "fuction calls" (to put it simply) and pathways that reference other calls and other pathways, over and over upon itself for a hundred million lines.
Its not the listing of the GTAC code (ie, genetic map) that's really necessary. Though of course it plays a part. Its the understanding of such code, what it does and what it controls, where power lies.
The guys interviewed all guessed it would be a hundred years or more before we began truly understanding what "functions" do what in the DNA strand and how it affects the organism in question.
Food for thought.