Not possible to see now because it is not available in shops. It is a future reality that may emerge as DNA based microprocessor. DNA based computing is an emerging technology using the biomolecule DNA as the data storage molecule. It is possible since DNA is doing data storage in the form of genetic information. If DNA computers emerge, it can store billions of times more data than the present computer. The DNA molecule of genes has the potential to perform calculations many times faster than the present microprocessors. By using the Nanotechnology, it is possible to create Nano computers to replace the Silicon based computers.
The idea of DNA computer came from Leonard Adelman, a computer scientist at the University of South California in 1994 to solve complex mathematical problems. The first DNA computers are unlikely to feature word processing, e-mailing and solitaire programs. Unlike conventional computers, DNA computers perform calculations parallel to other calculations. Conventional computers operate linearly, taking on tasks one at a time. It is parallel computing that allows DNA to solve complex mathematical problems in hours, whereas it might take electrical computers hundreds of years to complete them.
DNA Computing is the computational technology that uses the biomolecule DNA in the place of silicon based chips.DNA computing is otherwise known as the Bio molecular computing and is a fast growing interdisciplinary field that uses molecular biology and computer techniques in research and bio informatics areas.
The DNA computing technique was developed by Leonard Adleman of the University of South California in 1994.In 2002 a programmable bio computing machine was developed using DNA as the major element. In 2004, a DNA computer was designed to study the changes in cancerous cells. In 2009 a bio computer coupled with silicon chips was introduced which was based on enzyme systems and silicon chips. This marked great advancement in the field of Synthetic biology to use integrated systems of biological molecules and electronic chips.
DNA is the most stable molecule in the biological world and the genetic informations are encoded in it in the form of nitrogen base s Adenine, Guanine, Cytosine and Thymine, AGCT, the so called letter alphabets. These nitrogen bases have similarities with the binary coding of computers. So it is possible to use DNA as a storage device. DNA offers many advantages than the silicon based chips. These include
1. There are plenty of organisms like bacteria, so the supply of DNA is not a problem. This makes the DNA as a cheap resource.
2. DNA chips can be made non toxic
3. Size of the computer will be too small to keep in the pocket.
DNA computing exploits the functional properties of DNA. All living organisms except a few viruses carry DNA in the cells as genetic material. The DNA encodes all the information regarding the development, growth and functioning of the organisms.DNA molecule consists of Nucleotides having nitrogen bases –Adenine, Guanine, Cytosine and Thymine- pentose sugar and Phosphate group. The DNA has two anti parallel strands which dissociates and recombines when heated. DNA uses ATP (Adenosine Tri Phosphate) as fuel for the dissociation or re association of the strands. The energy in the form of ATP in DNA can carry out quick dissociation or recombination of the strands.
Technique of DNA computing
DNA computing uses different techniques for computational analysis. The most common methods are construction of logic gates such as AND, NOT, OR etc. from the DNA bases. Other methods in DNA computing includes use of DNAzymes, DNA tilling, PCR etc.
DNA as Enzyme
DNAzymes are DNA molecules with catalytic property. They catalyze the reaction when make contact with oligonucleotides. So the DNAzymes can be treated as the “input system” which can be used to create logic gates similar to silicon chips. The DNAzymes logic gates change its structure when make contact with the oligonucleotides. Two commonly used DNAzymes are E6 and 8-17 which are the best DNAzymes to create DNA logic gates.
Stem loop DNA
A Single stranded DNA with a loop at the end is called Stem loop DNA. It is highly dynamic and the loop opens and closes when a DNA segment is attached to it. This property is also used to create logic gates.
Sticky ends of DNA
The broken ends of DNA shows “sticky” nature and this property is used in DNA computing. The sticky DNA segment binds with another DNA molecule and displaces the segments apart. This property is exploited to create logic gates like AND, OR and NOT gates.
A DNA tile can be created using multiple sticky DNA segments. This method used DNA nano technology.DNA arrays can be constructed to implement computation.
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