Genetic make up of an organism or an individual lies in the $DNA$ sequences.

If two individuals differ, then their $DNA$ sequences should also be different, at least at some places.

These assumptions led to the quest of finding out the complete $DNA$ sequence of human genome.

With the establishment of genetic engineering techniques where it was possible to isolate and clone any piece of $DNA$ sequences, a very ambitions project of sequencing human genome was launched in the year $1990$ .

Human genome project [$HGP$]was called a mega project.

We can imagine the magnitude and the requirements for the project if we simply define the aims of the project as follows :

– Human genome is said to have approximately $3 $$\times 10^{9} \mathrm{bp}$ and if the cost of sequencing required is $US$ $3$ per bp, the total estimated cost of the project would be approximately $9$ billion $US$ dollars.

Further, if the obtained sequences were to be stored in typed form in books and if each page of the book contained $1000$ letters and each book contained $1000$ pages, then $3300$ such books would be required to store the information of $DNA$ sequence from a single human cell.

The enormous amount of data expected to be generated also necessitated the use of high speed computational devices for data storage and retrieval and analysis.

$HGP$ was closely associated with the rapid development of a new area in biology called Bioinformatics.