2. The common lysis solutions contain A. sodium chloride.
DNA extraction from Blood
Blood is the fluid part of the body in humans has many function such as transport of gases, nutrients, waste products, Regulation of pH and osmosis and Maintenance of body temperature.
Blood consist of red blood cells (RBCs), white blood cells (WBCs), platelets, and plasma. DNA which is the hereditary material in humans and other living organisms can be extracted from WBCs in the blood.
The common lysis solutions contain
A. sodium chloride.
B. Trimethamine (also known as tris) , which is a buffer to retain constant pH.
C. Ethylen diamine tetraacetic (EDTA) , which binds metal ions.
D. Sodium dodecyl sulfate (SDS) which is a detergent.
E. An enzyme used in DNA extraction is protienase K.

3. The main steps in DNA extraction:
Lysis:
Break down cells to access DNA in the nucleus
Destabilize hydrogen bonds, hydrophobic interactions, proteins Disrupts the association of nucleic acids with water in preparation to bind to silica membrane
Purification-Bind:
Separate purified DNA from cell material by adding Ethanol to enhance the binding of DNA to silica
Load sample to column and Centrifuge
DNA binds to the membrane and remaining lysate discarded

4. Purification – Wash:
Impurities and proteins should now have passed through the column and been discarded. The membrane, however, is still dirty with residual proteins and salt, if using blood it may be tinted yellow or brown
The column is washed with buffers to remove any residual impurities. There are typically 2 washes with a centrifuge step after each.
Wash 1 will contain a low amount of salt to remove any remaining proteins and colored contaminants
Wash 2 contains a high concentration of ethanol to remove the remaining salts. Salts MUST be removed for good DNA yields and purity. Wash 2 can be repeated to ensure this.
All ethanol MUST be removed so that the DNA can be successfully removed/eluted from the silica membrane. Centrifuge the sample until the column is completely dry.

5. Elution:
When elution buffer is added the nucleic acids become hydrated and will release from the membrane. If the column still has ethanol on it, the nucleic acids will not fully rehydrate and DNA store in the elution buffer.

6. • Elution Buffer (10 mM Tris-HCl, pH8.5 at 25ºC( . • GD Columns.
Kits
Various commercially available DNA extraction kits and systems are becoming increasingly popular because of their ease of use, limited labor, and ability to consistently produce high-quality DNA.
The genomic DNA Extraction Kit is optimized for genomic, mitochondrial and virus DNA purification from whole blood (fresh blood), serum, plasma, buffy coat, body fluids, cultured cells, tissue, hair, insects and sperm in one convenient kit.
This DNA extraction kit Applications PCR, RFLP, Southern Blotting, Real-time PCR.
Components:
• RBC Lysis Buffer.
• GT Buffer.
• GB Buffer.
• W1 Buffer.
• Wash Buffer.
• Elution Buffer (10 mM Tris-HCl, pH8.5 at 25ºC( .
• GD Columns.
• 2ml Collection Tubes.

7. Procedure:
Blood Sample Preparation
1. Blood Sample Preparation
Transfer up to300 μl of fresh whole blood and add 900 μl of RBC lysis buffer then mix by inversion.Incubate the tube for 10 min at room temperature, and then centrifuge for 5 min at 3000xg then remove the supernatant completely .Add 100 μl of RBC lysis buffer to re suspend the leukocyte pellet then proceed with cell lysis.
2. Cell Lysis
Add 200 μl of GB Buffer then mix by shaking vigorously. incubate at 60ºC for 10 minutes, inverting the tube every 2 minutes.
During incubation, transfer required volume of Elution Buffer (200μl/sample) to a 1.5 ml microcentrifuge tube and heat to 60ºC (for Step 5 DNA Elution(.
Optional RNA Removal Step
For RNA-free gDNA, following GSB Buffer addition and 60ºC incubation, add 5 μl of RNase A (50 mg/ml) and mix by shaking vigorously. Incubate at room temperature for 5 minutes to ensure efficient RNA degradation.
3. DNA Binding
Add 200 μl of absolute ethanol to the sample lysate and mix IMMEDIATELY by shaking vigorously for 10 seconds. If precipitate appears, break it up as much as possible with a pipette. Place a GS Column in a 2 ml Collection Tube. Transfer all of the mixture (including any insoluble precipitate) to the GS Column. Centrifuge at 14-16,000 x g for 1 minute. Following centrifugation, if the mixture did not flown through the GS Column membrane, increase the centrifuge time until it passes completely. Discard the 2 ml Collection Tube containing the flow-through then transfer the GS Column to a new 2 ml Collection Tube.
NOTE: It is important that the lysate and ethanol are mixed thoroughly to yield a homogeneous solution.

8. Checking for Degradation DNA
4. Wash
Add 400 μl of W1 Buffer to the GS Column. Centrifuge at 14-16,000 x g for 30 seconds then discard the flow-through. Place the GS Column back in the 2 ml Collection Tube. Add 600 μl of Wash Buffer (make sure absolute ethanol was added) to the GS Column. Centrifuge at 14-16,000 x g for 30 seconds then discard the flow-through. Place the GS Column back in the 2 ml Collection Tube. Centrifuge again for 3 minutes at 14-16,000 x g to dry the column matrix.
5. Elution
Transfer the dried GS Column to a clean 1.5 ml microcentrifuge tube. Add 100 μl of pre-heated Elution Buffer, TE Buffer or water into the CENTER of the column matrix. Let stand for at least 3 minutes to allow Elution Buffer, TE Buffer or water to be completely absorbed. Centrifuge at 14-16,000 x g for 30 seconds to elute purified DNA.
DNA can be stored at 4oC for extended periods, however for long term storage, - 20oC is preferable. Avoid repetitive freeze thawing of DNA, since this can cause degradation.
Checking for Degradation DNA
Running your sample through an agarose gel is a common method for examining the extent of DNA degradation. Good quality DNA should migrate as a high molecular weight band, with little or no evidence of smearing.