DNA SEQUENCING

 

                                          

WHAT DO YOU KNOW ABOUT THE DNA SEQUENCING?

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Growth and development information of an organisms is present in DNA of its genome.DNA sequencing is the process of determining the precise order of a nucleotide within a DNA molecule. DNA is used to determine the order of four bases A, T, G, and C in a strand of DNA. The first DNA sequence is determined in 1970s. DNA sequence allows faster and more individualized medical care to be administered. DNA sequencing is easier and gives order of magnitudes faster. In DNA sequencing the DNA is really just a template that is used to create a series of fragments. Fragments differ in length by one base and can be separated by size before there bases are identified. DNA sequence is used to determine the single, cluster of genes and full chromosome of organism. There are two main methods of DNA sequencing

1.      Maxam and Gilbert method

2.      Sanger method.

SANGER SEQUENCING

MAXAM GILBERT METHOD

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NEXT GENERATION SEQUENCING (NGS)

Ø SANGER SEQUENCING

Is usually the method of DNA sequencing which utilizes 2’3 ‘- dideoxynucleic triphosphate (ddNTPs). ddNTPS are terminator molecules. It was developed by the F.SANGER. IN this method the samples divided into four separate sequencing reactions which contains all standard deoxyribonucleotides. The DNA bands may be visualized by autoradiography or UV light and we can directly read the X-ray film or gel image. Sanger sequencing requires DNA synthesis.

Ø MAXAM GILBERT SEQUENCING

MAXAM gilbert is another type of dDNA sequencing. This method is developed by Allan Maxam Walter Gilbert in 1976-1977. This method breaks DNA at different nucleotides. Automation is not available. This method s possible for both single stranded DNA and double stranded DNA.  It on a gel.it used in purification of the DNA fragment of sequence.

Ø NEXT GENERATION SEQUENCING

Technologies developed after the Sanger automated method are known as next generation sequencing. The one advantage of NGS is that it enables the sequencing of biological codes at very rapid pace with low cost per operation our conventional methods. The major platforms for NGS are SOLID AND SOLEXA. NGS is technologies for sequencing is combination of strategies for

·         Template preparation

·         Sequencing and imaging

·         Genome alignment

·         Assembly methods

A human gene can be configured in a single day by using NGS.