DNA extraction from onion cells

DNA, or deoxyribonucleic acid, is the hereditary material in almost living "things".
Nearly every cell in a person’s body has the same DNA. Most of DNA is located in cell nucleus. We can say this DNA is like a stepladder and it can be as long as 1,80m but it can fold itself so tight it can be stored in a small space with micro dimensions.

Lets see how we can see this DNA without any microscopy help.

We need:

• 2 bowls, one of them must be transparent,
• a knife,
• a onion,
• dish detergent,
• salt,
• water,
• 2 spoons,
• alcohol.

How to:

1. Peel the onion;
2. Cut the onion, into small pieces, to the bowl;
3. Add some dish detergent, enough to cover it;
4. Add the salt (1/2 tablespoon);
5. Finally add the water (2 tablespoons);
6. Mix, careful, we don't want it to form bubbles;
7. Wait 20 min;
8. Mix again;
9. Separate the liquid layer from the rest, the DNA is on the liquid, reject the rest.
10. Add alcohol to the liquid, slowly, we want the alcohol to form a second layer above the liquid, try to make the alcohol run down the bowl wall.
11. Don't mix the layers;
12. Wait another 20 min.

What happens?
You can see small white strands; some of them may look like small clusters.

Why?
DNA precipitates when mixed with alcohol; this means it's not soluble in this reagent. This causes the DNA to clump together when there is a lot of it. And, usually, cells contain a lot of it!

NOTES:
Salt- Helps DNA to precipitate
Cold water- Helps to maintain DNA intact. If we use hot water cellular enzymes can destroy the DNA strand.

Et voilá!
Genetic in your kitchen!

Enjoy!