PRESENTATION ON

BIOINFORMATICS

DNA SEQUENCING PROCESS

GROUP MEMBER

SAJIBUL HASSANNAHIAN AHMEDTARIQUL ISLAMMONSUR AHMED SHAFIQOMAR FARUQ

NAHIAN AHMED ID- 151-15-5137

DEOXYRIBONUCLEIC ACID Deoxyribonucleic acid (DNA) is a nucleic

acid that functions include:->Storage of genetic information->Expression of the genetic message

DNA’s major function is to code for proteins. Information is encoded in the order of the nitrogenous bases.

DNA SEQUENCINGDetermining the order of bases in

asection of DNA.

To analyze gene structure and itsrelation to gene expression as well

asprotein conformation

HISTORY

• Deoxyribonucleic acid (DNA) was first discovered and isolated by Friedrich Miescher in 1869

• 1953 structure of DNA established as a double helix

• 1970 first method of DNA sequencing involved a location specific primed extension strategy.

• 1977 Frederick sanger published a method for DNA sequencing with chain terminating in hibitors.

• 1990 several new methods are developed in the mid to late90,s

• 2003 complete human genome project

History

SAJIBUL HASSAN ID-151-15-4986

DNA Sequencing is used for:• Mapping genomes• Determining gene structure• Detecting polymorphism• Analyzing genetic variation• Predicting the possible product(s) of DNA fragments• Many purposes depending on the questions one is asking

DNA SEQUENCING METHOD

Methods of DNA sequencing :1.Maxam-Gilbert sequencing2.Chain termination method (Sanger method)

Next generation methods:1.Massively parallel signature sequencing2.Polony sequencing 3.Pyrosequencing4.Illumina sequencing5.Solid sequencing

SANGER METHOD• Most common approach used for DNA

sequencing .

• Invented by Frederick Sanger - 1977 • Nobel prize - 1980

• Also termed as Chain Termination or Dideoxy method

TARIQUL ISLAM ID -151-15-5144

STEP - 1The reaction mixture

• It sorts the newly synthesized DNA strands by length.

• The reaction mixture is heated to keep the newly synthesized strands separated

• Separated strands are loaded onto a tiny capillary tube

• The tube is not much thicker than a human hair and is 1 to 3 feet long

STEP - 2

1.The emerged strands are passed through a laser beam

2.The beam causes the dye to glow at a specific wavelength, or color. This color is then detected by a photocell

STEP - 3

• Computers read the sequence from the gel and interpret the colors and print a sequence of nucleotides across the top.

STEP - 4

MONSUR AHMED SHAFIQ

COMPARISON

Sanger Method Maxam Gilbert MethodEnzymatic Chemical

Requires DNA synthesis

Requires DNA

Termination of chain elongation

Breaks DNA at different nucleotides

Automation Automation is not available

Single-stranded DNA

Double-stranded or single- stranded DNA

MORDEN APPLICATIONS OF DNA SEQUENCING

• Forensics: to help identify individuals because each individual has a different genetic sequence

• Medicine: can be used to help detect the genes which are linked to various genetic disorders such as muscular dystrophy.

• Agriculture: The mapping and sequencing of a genome of microorganisms has helped to make them useful for crops and food plants.

OMAR FARUQID-151-15-5444

HUMAN GENOME PROJECT

• The biggest challenge for the life sciences

• 15 years project (NIH, DOE of USA)

• Primary goal Sequence base pairs of human beings that form DNA

• Identifying & mapping approx. 20K-25K genes

• Significance Physical & functional•standpoint

ADVANTAGES• Improved diagnosis of disease• Identify the genes causing genetic

diseases• Identifying crime suspectsDISADVANTAGES

• Whole genome cannot be sequenced at once

• Very slow and time consuming

Thank You!!!