Sandeep M1bj05cs032

Contents Traditional Computers Introduction to DNA Structure of DNA DNA Computers Advantages & Disadvantages Develoments in DNA Computing References

Traditional Computation Traditional computers started with vacuum

tubes, mechanical switches. Now we have IC’s and processors with

VLSI, ULSI technologies. These computers are examples of Von

Neumann architecture.

Traditional Computation(continued) Silicon is the life for today's computers. Moore’s Law states that silicon

microprocessors double in complexity roughly every two years.

One day this will no longer hold true when miniaturisation limits are reached.

Require a successor to silicon.

What is DNA ? Deoxyribonucleic acid (DNA) is a nucleic

acid that contains the genetic instructions used in the development and functioning of all known living organisms.

DNA is nothing but blueprint or a code, since it contains the instructions needed to construct other components of cells, such as proteins and RNA molecules.

Structure of DNA

Structure of DNA(continued) Chemically, DNA consists of two

long polymers of simple units called nucleotides, with backbones made of sugars and phosphate groups joined by ester bonds.

These two strands run in opposite directions to each other and are therefore anti-parallel.

There are 4 nucleotides in DNA A – Adenine T –Thymine

C – Cytosine G – Guanine

DNA Computing DNA computing is a form

of computing which uses DNA, biochemistry and molecular biology, instead of the traditional silicon-based computer technologies.

This field was initially developed by Leonard Adleman of the University of Southern California, in 1994.

DNA Computing(continued) Adleman demonstrated a proof-of-

concept use of DNA as a form of computation which solved the seven-point Hamiltonian path problem.

DNA computers are faster and smaller than any other computer built so far. But DNA computing does not provide any new capabilities from the standpoint of computability theory .

Computation Algorithm STEP1:Encode the city names in short DNA

sequences . Encode the Itineraries by connecting the city sequences for which the routes exist .

The DNA molecules are generated by a machine called DNA synthesizer

CITY DNA SEQUENCE

MUMBAI GCTACG

DELHI CTAGTA

BANGALORE TCGTAC

CHENNAI CTACGG

KOLKATA ATGCCG

•Polymerase chain reaction is used to produce many copies of the DNA•PCR is iterative and uses an enzyme called polymerase•Polymerase copies a section of single stranded DNA starting at the position of the primer, which is DNA complimentary to one end of the Interested section.

Step 2: Sort the DNA by length and select the DNA whose length Corresponds to 5 cities.

• Gel electrophoresis force the DNA through a gel matrix by using an electric field.

• DNA forces its way through the gel which slows down the DNA at different rates.

STEP 3:Successively filter the DNA molecules by city, one city at a Time.•Finally, use affinity separation procedure to weed out paths without all the cities

•Iterative procedure (for each vertex/city)•Probe molecules attached on iron balls attract the correct strands; the rest is poured out

•If any DNA is left in the tube, it is the Hamiltonian Path.

Advantages The power of DNA in view of computation

capability: vast parallelism: 10 trillion ligation reaction

could be done simultaneously in a marble-sized space.

exceptional energy efficiency: 2×1019 operations/J, theoretical bound 3×1019 operations/J, existing computer: 109 operations/J.

extraordinary information density: 1gram = 4×1021 bits = 1 trillion CDs.

Disadvantages DNA computing involves a relatively large

amount of error. Requires human assistance! Time consuming laboratory procedures. No universal method of data

representation. DNA has a half-life.

Solutions could dissolve away before the end result is found

DNA V/s Conventional Computer

Developments in DNA computation Began in 1994 when Dr. Leonard Adleman

wrote the paper “Molecular computation of solutions to combinatorial problems” & succeeded in using it.

First practical DNA computer unveiled in 2002 by Olympus Optical Co., Ltd . Used in gene analysis.

DNA computer for gene analysis (development prototype).

High-speed fully-automated process from sample injection to reaction enables quantitative gene expression profiling.

Developments in DNA computation(continued)

Self-powered DNA computer unveiled in 2003.>First programmable autonomous computing machine in

which the input, output, software and hardware were all made of DNA molecules.

>Can perform a billion operations per second with 99.8% accuracy

• In 2004 an autonomous DNA computer that is capable of diagnosing cancerous activity within a cell, and then releasing an anti-cancer drug upon diagnosis is constructed by Prof. Shapiro & team. They claim in the journal Nature that they were successful.

Developments in DNA computation(continued) A DNA Sequence Design for Direct-Proportional

Length-Based DNA Computing using DNASequenceGenerator is developed in Universiti Teknologi Malaysia in 2008.

A Method to Encrypt Information with DNA Computing has been suggested by Zheng Zhang, Xiaolong Shi, Jie Liu of Department of Control Science and Engineering, Huazhong Univ of Sci&Tech,China in 2008.

Conclusion DNA computers showing enormous

potential, especially for medical purposes as well as data processing applications.

Many issues to be overcome to produce a useful DNA computer.

References www.news.nationalgeographic.com/news/

2003/02/0224_030224_DNAcomputer.html - www.cnn.com www.sciam.com/article.cfm?articleID=000A4F2E-

781B-1E5A-A98A809EC5880105 http://unisci.com/stories/20021/0315023.htm www.howstuffworks.com www.bbcworld.com www.wikipedia.com IEEE papers on DNA computing

Thank you…