DNA Sequencing
DNA sequencing determines the nucleic acid sequence ( order and the nucleotides )
of a DNA fragment .
It allows determining sequence of individual genes ,
clusters of genes , operons ,
full
chromosomes ,
entire genomes of an
organism .
It's important in evolutionary biology (how different organisms are related and how they
evolved) , changes in genes ,
associations with diseases and phenotypes identify potential
,
drug targets .
take place
DNA sequencing essential step before bioinformatics can .
Frederick method of DNA sequencing in 1977
Sanger created automated .
Early methods of DNA Sequencing :
The Sanger Method called chain -
termination method This .
is a preferable
method due to relative ease , reliability , use of fewer toxic chemicals and lower amount
of radioactivity than Maxam + Gilbert method .
How DNA sequencing is done :
•
DNA is isolated and purified .
•
Hydrogen bonds are broken down by applying heat .
in single strand Iss) all 4 nucleotides
•
Resulting a DNA .
DNA polymerase enzyme and ,
are added into 4 separate tubes .
•
To each of the 4 tubes limited quantities of
,
one of the 4 DDNTB are added to each tube
respectively .
ddNTPs
They differ from DNTB by lack of free 301-1 group on the 5- carbon sugar .
If a DDNTP is added to growing DNA Strand ,
the chain is not extended
any further because
'
the free 3 OH group needed to add another nucleotide is not available .
DNA sequencing determines the nucleic acid sequence ( order and the nucleotides )
of a DNA fragment .
It allows determining sequence of individual genes ,
clusters of genes , operons ,
full
chromosomes ,
entire genomes of an
organism .
It's important in evolutionary biology (how different organisms are related and how they
evolved) , changes in genes ,
associations with diseases and phenotypes identify potential
,
drug targets .
take place
DNA sequencing essential step before bioinformatics can .
Frederick method of DNA sequencing in 1977
Sanger created automated .
Early methods of DNA Sequencing :
The Sanger Method called chain -
termination method This .
is a preferable
method due to relative ease , reliability , use of fewer toxic chemicals and lower amount
of radioactivity than Maxam + Gilbert method .
How DNA sequencing is done :
•
DNA is isolated and purified .
•
Hydrogen bonds are broken down by applying heat .
in single strand Iss) all 4 nucleotides
•
Resulting a DNA .
DNA polymerase enzyme and ,
are added into 4 separate tubes .
•
To each of the 4 tubes limited quantities of
,
one of the 4 DDNTB are added to each tube
respectively .
ddNTPs
They differ from DNTB by lack of free 301-1 group on the 5- carbon sugar .
If a DDNTP is added to growing DNA Strand ,
the chain is not extended
any further because
'
the free 3 OH group needed to add another nucleotide is not available .
