The document provides an overview of DNA isolation, detailing its aims, definitions, purposes, sample selection, and the basic steps involved in the process. Key points include the chemistry behind cell lysis, precipitation methods for DNA extraction, and the importance of sample type for successful DNA recovery. It highlights both scientific and forensic applications of DNA isolation, emphasizing its relevance in diagnostics and identification.

1. Basics of DNA Isolation
Prepared by: Md Abu Bakar Siddik
Matrikelnummer: 21435158
Name of module : Molecular and
biological methods in plant and animal
breeding.
Date: 03.08.17
George-AugustUniversität, Göttingen
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2. 1. Aim of DNA isolation
2. Definition DNA
3. Definition of DNA isolation
4. Purposes of DNA isolation
5. Sample selection
6. Steps of DNA isolation
7. Chemistry behind it
Outline
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3. AIM Of DNA Isolation
Seperate the DNA that is present in the nucleus
of the cell from other cellular components.
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4. Definition of DNA
• DNA is the hereditary material that is present in all living
organisms . It is polymer of nucleotides. B-DNA most
common.
DNA
Nuclear DNA Mitochondrial DNA
https://ghr.nlm.nih.gov/primer/basics/dna 4

5. Definition : DNA isolation is the extraction process of DNA
from various sources by using both chemical and physical
methods.
• First done by Swidish physician Friedrich Miescher in
1869.
Purposes:
• Scientific : Isolation of specific DNA in plant or animal cell for
diagnostic puspose gene cloning
•Medicine : To identify specific source or virulence of organisms
in community or hospital.
•Forensic : To identify the individuals like rapists, war victims,
thives, paternity identification.
Fig: F. Miescher
DNA Isolation
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6. Sample Selection
Tissue sample
• Good sample: muscle liver, spleen bone marrow
•Bad sample: cartilage, adipose tissue, connective tissues
Semen: very good ,high dense quality.
Blood cell: only in leukocytes
Plant sample : more difficult due to cell wall, polysaccharides
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7. Basic principles or steps of DNA Isolation
1. Cell lysis
2. Isolation of DNA from mixture
Precipitation
Adsorption
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8. Chemistry behind
Cell lysis: Means lysis or breakdown of tissues or cells.
• Salt solution: Detergent eg, Sodium dodecyl sulphate(SDS) –
to destroy the cell membrane and lipids.
• For protein denaturation: Proteinase K enzyme, DNAase enzyme
and histone
•For sperm: Dithiothreitol (DDT) – to breakdown the disulfide
bond of sperm coat.
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9. Diffrent cell components like protein, DNA, RNA, saccharides,
lipidsare lysate togeter.
1. Precipitation of protein- high salt concentration- induced
by Nacl, acetate
- organic solvent – chloroform, Phenol
Chloroform: It solubilizes lipids and lot of proteins to remove them
from DNA.
• 2 distinct phase.
• A) Lower phase- chloroform with protein and polysaccharides.
• B)Lower phase: DNA with deionized water
Isolation of DNA from mixture:
Chemistry Behind
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10. Precipitation of DNA
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Source: Prof. Tetens

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2. Precipitation of DNA – Ethanol or isopropanol.
a.) Isopropanol: DNA is less soluable in isopropanol
containing solution than solution containg ethanol.
• Easier to perform in room temperature that lessen the
risk of coprecipitation of DNA with Nacl or others.
Chemistry behind
Isolation DNA from mixture :

12. Adsorption – It means Binding of DNA with a solid phase.
- Only ion exchanger column is capable to bind with
DNA,whereas, the other components will be discarded
Chemistry behind
b.) Ethanol: Chilled ethanol only dissolves the DNA. Colder
ethanol makes slower the activity of enzymes which
can break down the DNA, thus giving better result.
2. Precipitation of DNA –
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13. Extraction of DNA
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14. Thank you for
your attention
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15. Reference
1. https://ghr.nlm.nih.gov/primer/basics/dna
2. https://en.wikipedia.org/wiki/Friedrich_Miescher#/media/File:Friedrich_Miescher.jpg
3. https://bioprep.community.uaf.edu/learning-modules/2-dna-extraction-4/the-basics-of-dna-extraction/
4. https://www.slideshare.net/zohaibkhan404/role-of-chemicals-used-in-dna-extraction-recombinant
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