Introduction:
DNA isolation is a process of purification of DNA from a mixture of biomolecules in the
sample using a combination of physical and chemical methods. 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 sequencing, fingerprinting, restriction fragment
length polymorphism, construction of genomic 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. The quantity, quality and integrity of DNA will directly affect experiments and results.
In prokaryotic cell DNA is localized in the nucleoid, whereas in eukaryotic cell DNA is localized in
the nucleus. The nucleus contains about 90% of the total cellular DNA, the remaining DNA is in
other organelles like mitochondria, chloroplasts or kinetochores. In viruses and bacteriophages,
the DNA is encapsulated by a protein coat.
During extraction/isolation, the DNA is separated from proteins, membranes, and other
cellular material contained in the cell. This extraction can be one of the most labour-intensive
parts of DNA analysis. Extraction methods may require an overnight incubation or a protocol that
can be completed in minutes or a couple of hours, or may be shortened using commercially
available reagents wherein all these laborious steps can be skipped. The DNA extraction process
requires careful handling of biological material to prevent sample contamination and crossover.
DNA isolation is a process of purification of DNA from a mixture of biomolecules in the
sample using a combination of physical and chemical methods. 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 sequencing, fingerprinting, restriction fragment
length polymorphism, construction of genomic 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. The quantity, quality and integrity of DNA will directly affect experiments and results.
In prokaryotic cell DNA is localized in the nucleoid, whereas in eukaryotic cell DNA is localized in
the nucleus. The nucleus contains about 90% of the total cellular DNA, the remaining DNA is in
other organelles like mitochondria, chloroplasts or kinetochores. In viruses and bacteriophages,
the DNA is encapsulated by a protein coat.
During extraction/isolation, the DNA is separated from proteins, membranes, and other
cellular material contained in the cell. This extraction can be one of the most labour-intensive
parts of DNA analysis. Extraction methods may require an overnight incubation or a protocol that
can be completed in minutes or a couple of hours, or may be shortened using commercially
available reagents wherein all these laborious steps can be skipped. The DNA extraction process
requires careful handling of biological material to prevent sample contamination and crossover.
