INNOVATIONS FROM THE EDGE - KPIT

Fig 4: 3D structure of the DNA binding in human polymerase [6]
Ligases bind molecules together. They are used to
bind two strands of DNA in proximity into one
single strand.
3. Gel electrophoresis
Electrophoresis is the movement of charged
molecules in an electric field. In gel
electrophoresis, a solution of heterogeneous DNA
molecules is placed at one end of slab of gel and
current is passed. The DNA molecules are
negatively charged and hence when they are
placed in an electric field they tend to migrate
towards positive charge. This process separates
the DNA molecules by length.
4. DNA Synthesis
Now it is possible to synthesize new DNA
molecules for required DNA sequence.The DNA
molecules are delivered dry in a small tube and
appear as a small, white and amorphous lump.
For his experiment, L. Adleman had chosen a
problem with seven cities shown in Fig 1. For
simplifying the discussion, it was reduced to four
cities connected by six flights shown in Fig 2. He
assigned a random DNA sequence to each city.
Then he assigned DNA flight number by
concatenating the last name of the start city and
the first name of the destination city. Adleman
took a pinch of each of different sequences in a test
tube and then he added water, salt, ligase and
some other ingredients to approximate the
conditions inside a cell. Any of the flight number
would meet the complementary of any of the four
cities, for example, Atlanta-Boston flight number
(GCAGTCGG) would meet the complementary of
the city Boston (AGCCTGAC). Here the former ends
with TCGG and the latter starts with AGCC. Since
these were complementary, they stuck together.
The resulting complex would have met Boston-
Chicago flight number and formed longer complex
in a similar manner. The solution for the map shown
i n t h e F i g 2 h a d o n l y o n e s o l u t i o n
GCAGTCGGACTGGGCTATGTCCGA.
Research and Applications
DNA computer finds its main applications in
applied sciences. One such field is combinatorial
chemistry. Combinatorial chemistry involves
construction of enzymes, other molecules and
generating sequences of RNA (Ribonucleic acid),
particularly used in bio-molecular engineering and
medicines. Adleman stated that combinatorial
chemistry is similar to DNA computation as it
involves generating sequence of RNA and
searching for molecules with desired properties.
Another area where these bio-molecular machines
find application is nanotechnology and majorly in
nano-fabrication where both the computational
ability of DNA is used along with the manufacturing
ability of RNA.
We can look at DNA models to play potential role in
the field of computers. With the natural storing ability
along with the computational ability, they definitely
stand a chance to prove a point in this field. A group in
California has done significant research in the field of
DNA computing and has made up a structure of 74
DNA molecules to perform square root computation.
This is one of the
34 TechTalk@KPITCummins, Volume 5, Issue 1, 2012