This document summarizes the key steps in DNA isolation: cell lysis to break open cells, protein removal to separate DNA from proteins, centrifugation to separate molecules by density, and DNA purification to isolate DNA from other cellular components. It defines DNA isolation as extracting DNA and discusses its importance in research. The four main methods of DNA isolation are listed as cell lysis, protein removal, centrifugation, and DNA purification.

1. SUBMITTED BY: UME HABIBA
SUBMITTED TO : MAM IQRA
PROGRAM: BS BOTANY 7TH SMESTER
ASSIGNMENT NO 1
METHOD OF DNA ISOLATION

2. CONTENT
• Introduction
• Define DNA isolation
• Methods of DNA isolation
• Name of methods
• Cell lysis
• Protein removal
• Centrifugation
• DNA purification

3. INTRODUCTION TO DNA ISOLATION
• DNA isolation is an essential technique in molecular biology.
• Isolation of high-molecular weight DNA has become very important with the increasing demand for DNA fingerprinting, restriction fragment
length polymorphism (RFLP), construction of genomic or sequencing libraries and PCR analysis in research laboratories and industry.
• Also, DNA isolation is the first step in the study of specific DNA sequences within a complex DNA population, and in the analysis of genome
structure and gene expression
• chloroplasts or kinetochores. In viruses and bacteriophages, the DNA is encapsulated by a protein coat, and constitutes between
30 and 50 percent of the total mass of the virion. In prokaryotic and eukaryotic cells, DNA constitutes only about 1% of the total
mass of the cell. The approximate composition of rapidly dividing E. coli cells and human cell.

4. DEFINE DNA ISOLATION
• The first isolation of deoxyribonucleic acid (DNA) was done in 1869 by Friedrich
Miescher.
• Currently, it is a routine procedure in molecular biology or forensic analyses.
• For the chemical method, many different kits are used for extraction, and
selecting the correct one will save time on kit optimization and extraction
procedures.
• PCR sensitivity detection is considered to show the variation between the
commercial kits.

5. METHOD OF DNA ISOLATION
There are 4 methods of DNA isolation
• Cell lysis
• Protein removal
• Centrifugation
• DNA Purification

6. CELL LYSIS
• Lysis is the breaking down of the membrane of a cell, often
by viral, enzymic, (that is,the mechanisms that compromise its
integrity.
• A fluid containing the contents of lysed cells is called a lysate.
• In molecular biology, biochemistry, and cell biology laboratories, cell
cultures may be subjected to lysis in the process of purifying their
components, as in protein purification, DNA extraction, RNA extraction,
or in purifying organelles.

8. PROTEIN REMOVAL
• Protein removal is an important step in the DNA extraction procedure because protein contamination directly
attacks the nucleic acids such as DNA or RNA in the samples.
• The method is PEI (polyethyleneimine) precipitation.
• ln essence, you add PEI to your protein solution to a final concentration of 0.02%, stir on ice for a half hour while
the nucleic acids are precipitated from solution, centrifuge to remove the precipitated material, and you're done.
• Biological samples commonly contain proteins that interfere with downstream applications.
• The CRASH method, in which the protein is denatured with solvents such as acetonitrile and methanol and the
proteins filtered out, is often the preferred method for removal.

9. CENTRIFUGATION
• Centrifugation is a method of separating molecules having different densities by spinning
them in solution around an axis (in a centrifuge rotor) at high speed.
• It is one of the most useful and frequently employed techniques in the molecular biology
laboratory.
• Centrifugation is used to collect cells, to precipitate DNA, to purify virus particles, and to
distinguish subtle differences in the conformation of molecules.
• Most laboratories undertaking active research will have more than one type of centrifuge,
each capable of using a variety of rotors.

10. DNA PURIFICATION
• Basically, you can purify your DNA samples by lysating your cell and/or tissue samples using the
most appropriate procedure (mechanical disruption, chemical treatment or enzymatic digestion),
• lsolating the nucleic acids from its contaminants and precipitating it in a suitable buffer solution.
• Most of these methods include the following steps: leukocyte isolation or red cell lysis, nuclear lysis,
deproteinization, RNAse-A treatment, and DNA precipitation.
• Several commercial products are available for rapid purification of high-quality genomic DNA from
blood spots, whole blood, and other sources.