DNA Extraction

To study DNA and learn how our genes function, scientists must be able to work with DNA itself, outside the protective walls of the nucleus and cell membrane. So researchers have learned to separate (to isolate or extract) - DNA from the proteins and other substances in the cell.

Kristin Darden, Janelle Moran, Deb Semmler

Before we get into this, though, let’s do a bit of review.

What is DNA?

Deoxyribonucleic Acid

That’s a mouthful. Rather than going through a long drawn out explanation, try this Tour of the Basics to refresh your memory.

DNA is a hardy molecule, and one of the largest known. To work with it, we need to extract it from the other cellular materials.

Us old folks will remember Oliver

Hardy.

Get it- Hardy? →

So what would you use the isolated DNA for?

Extraction of DNA is often an early step in many diagnostic processes used to detect bacteria and viruses in the environment as well as diagnosing disease and genetic disorders.

That’s great, but I’m not a geneticist. Why would I do this

process in my class?

‘Cuz DNA is cool to look at with your students!

Okay, I’m listening- so what is DNA Extraction?

Simply put, DNA extraction is the removal of deoxyribonucleic acid (DNA) from the cells or viruses in which it normally resides.

So how do I extract the DNA?

Start by breaking the cells open to expose the DNA within.

Then remove the nuclear membrane lipids by adding a detergent.

Finally precipitate the DNA with an alcohol. This step will also remove alcohol-soluble salts.

Yeah, right- want to run that by me again?

It’s not as difficult as it sounds.

Any age student can do it- from kindergarten to AP Biology students.

It doesn’t require any fancy laboratory equipment, if you don’t have it.

You can make it as simple or as complex as you’d like.

Watch this to see how simple it can be.

strawberry extraction

Now obviously, that was a bit too simple for your intermediate classes, so here’s another video that gives you an idea for that.

Kiwi extraction demo

WHERE DOES THIS FIT?http://www.doe.in.gov/standards/core.html

State Standards

3rd Grade3.1.23.1.33.1.43.1.53.2.23.2.43.2.6

5th Grade5.1.15.1.25.1.35.2.45.2.75.4.15.4.25.4.3

Biology I

B.1.1B.1.21B.1.26B.1.27B.2.4

Resources for lessons plans, tutorials, videos, labs

• Virtual DNA isolation lab – this is an excellent hands-on presentation that can be used as an introduction or review of the DNA isolation lab.

• DNA isolation lab – this is the lab we did in the preparation of our DNA for gel electrophoresis. Copies of the PCR lab and gel electrophoresis are also included.

• How to Extract DNA from Anything is a good choice if you would want to make comparisons about the different amounts of DNA formed from different organisms or you would like to vary some of the reagents.

• Make Your Own DNA Necklace is a fun activity- you can even sell them around Valentines Day as a fund raiser- i.e. “Why Give Candy and Flowers- Give Your Loved One a Piece of Yourself”!

More Resources • DNA Overview –explains what DNA is and

includes lots of additional information.• NOVA – this Nova site has videos (good for

middle to high school age) and it includes classroom activities, links to books, case studies, etc.

• From the Beginning- from early elementary to college, this site explains pretty much anything you would want to know about genetics.