Does anyone have experience of extracting DNA out of dairy cow's milk? I am interested in the DNA present in the B-cells. I have done extraction from blood but want to try extraction from milk. I have tried centrifuging the milk i) 2000 g, 20 minute, 4 C, or ii) 5000 g, 30 mins, 4 C in a falcon tube. I find the fat layer on top very difficult to get rid of and will contaminate the pellet at the bottom even after washing with PBS. Additionally, there are debris contamination in the pellets. The DNA yield from the pellet were not good and the target gene was not seen in the PCR amplification process. I used commercial spin-column based DNA extraction kit.
I haven't done this exact protocol, but you could try a spin column with a cap on the bottom to avoid the fat layer. Spin, remove the bottom cap, save the lower layer, toss the fat.
This is how it could work:
- put 700µl of milk together with 700µl of PBS together in a tube and mix well.
- centrifuge for 10min at 1500g
- gently take off the supernatans with a pipet and try to pipet the fat off first
- remove the fat/cream that is left on the walls of the tube with a sterile swab
- add 1ml of PBS to your pellet and mix well so the pellet is resuspended
- centrifuge for 10min at 1500g
- gently take off the supernatans with a pipet and try to pipet the fat off first
- remove the fat/cream that is left on the walls of the tube with a sterile swab
You should have obtained a pretty clean pellet by now otherwise you can wash again with 1ml of PBS
After this you can continue extraction with whatever extraction kit you currently use. Good luck with your experiment.
New Rapid Method of DNA Isolation from Milk Somatic Cells https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4806335/
Centrifuge 10 mL of raw milk at 7000 g for 10 minutes (4°C), remove the milk fat and most of the supernatant from above somatic cells and milk proteins pellet, and transfer the pellet with the remainder of the supernatant to a 2-mL sterile tube. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4806335/
Some of the most common DNA extraction methods include organic extraction, Chelex extraction, and solid phase extraction. These methods consistently yield isolated DNA, but they differ in both the quality and the quantity of DNA yielded. https://en.m.wikipedia.org/wiki/DNA_extraction
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