METHODOLOGIES

 The  HGP  researchers collected blood (female) or sperms (male) samples from large number of doners .

They used  white blood calls from blood of male and female doners .

For sequencing, the total DNA from call is isolated and converted into random fragments of smaller sizes approximately 150,000 base pairs in length .

These pieces then ligated to a type of vector known as bacterial artificial chromosome (BACs) the BACs are derived from bacterial chromosome which have been generally engineered .

The vector containing the pieces of  DNA  was inserted into bacteria (host).

In bacteria the pieces of DNA are copied by bacterial DNA replication. .

In this process several copies of DNA pieces were made, each piece of DNA fragment can be sequenced using automated DNA sequence developed by f. sanger who determined aminoacid  sequence of proteins.

 Another vector YAC (yeast artificial chromosome)  was also used for  above purpose. 

Sometime these sequences have some overlapping regions which can only be sequences with help of computer based programme .

The process of identifying all genes with their coding and non-coding sequence with function called sequence annotation and is the domain of bio-infomatics .

The methods involved for identifying all genes that expressed as RNA called expressed sequence  tags (ESTs).