From: "J. R. Molloy"  
Subject: DNA Nano-Computer

Test tube holds a trillion computers. 
http://news.bbc.co.uk/hi/english/sci/tech/newsid_1668000/1668415.stm 

A computer so small that a trillion of its kind fit into a test tube has been 
developed by researchers at the Weizmann Institute in Israel. Today it is limited 
to processing DNA which is synthetically designed. In the future it could process 
any DNA molecules The nanocomputer consists of DNA and DNA-processing 
enzymes, both dissolved in a liquid held in a test tube.

The inventors believe it could ultimately lead to a device capable of 
processing DNA inside the human body, finding abnormalities and creating 
healing drugs. In the medium term it could be turned into a tool capable of 
speeding up the currently labour intensive job of DNA sequencing.
>From salesmen to genomes DNA sequencing is part of the task of cracking the 
genetic code of interesting organisms as diverse as the pneumonia bug, the 
tomato and the human body to discover more about the way they function.

Professor Ehud Shapiro, head of the Weizmann team, says the DNA computer is 
an automaton, completing its work without human intervention at each stage 
of processing. "Today it is limited to processing DNA which is synthetically 
designed. In the future it could process any DNA molecules," he told BBC 
News Online. The machine's input, output and software program are all DNA 
molecules.  The Israeli team reads the output of the computer by running the 
liquid through an electrophoretic gel - the same process which produces the 
characteristic black and white bands of a DNA fingerprint.

Previous efforts DNA computing took a leap forwards in 1994 when Leonard 
Adleman of the University of Southern California used DNA to solve a problem 
commonly known as the travelling salesman problem. This problem sets the 
goal of working out the fastest way of visiting a given set of destinations. 
Prof Adleman, co-inventor of the RSA encryption scheme which protects most 
secure transactions on the internet today, was exploiting the advantages of 
DNA computing over conventional silicon. DNA stores a massive amount of data 
in a small space. 

Its effective density is roughly 100,000 times greater than modern hard disks.
And while a desktop PC concentrates on doing one task at a time very 
quickly, billions of DNA molecules in a jar will attack the same problem 
billions of times over. Nanoscale approach Prof Shapiro and his team have 
taken a different approach. Their goal was not to harness the power of 
biological computing to solve weighty mathematical problems, but to build a 
nanoscale computer which takes naturally-occuring information-bearing 
biological molecules such as DNA as an input. Their success in creating a 
nanomachine that works on synthetically produced short DNA strands is a huge 
step towards this goal.

Mathematical inspiration DNA computing research was inspired by the 
similarity between the way DNA works and the operation of a theoretical 
device known as a Turing machine and named after the British mathematician 
Alan Turing. "Turing machines process information and store them as a 
sequence, or list of symbols, which is very naturally related to the way 
biological machinery works," Prof Shapiro said. The nanomachine devised by 
his team is a special case of the Turing machine: a two-state, two-symbol 
automaton. It distinguishes between two symbols, like the zeroes and ones of 
a conventional electronic computer. The Israeli team's DNA computer is 
described in more detail in the journal Nature.
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Useless hypotheses, etc.: 
consciousness, phlogiston, philosophy, vitalism, mind, free will, qualia, 
analog computing, cultural relativism, GAC, Cyc, Eliza, cryonics, individual 
uniqueness, ego, human values, scientific relinquishment, malevolent AI, 
non-sensory experience We move into a better future in proportion as science 
displaces superstition.