Fun Friday – Five Fantastic Facts about DNA and how to extract DNA from a banana

Dr. Simple was explaining a little about DNA in the last post, so I thought I would share one of the first experiments my children ever asked me to do with them…. they wanted to see DNA, so we extracted it from a banana.

Did you know that we share approximately 50% of our DNA with bananas?
Did you know that we share approximately 50% of our DNA with bananas?


You will need

… a banana, a fork, a bowl, washing up liquid, ice cold surgical spirits (or isopropanol – both available from a pharmacy), salt, a sieve, a glass jar.


What to do…

Remove the banana skin and mash the banana in the bowl, using the fork. Add two teaspoons of washing up liquid and stir slowly.

Add a teaspoon of salt and one to two tablespoons of water and stir carefully.

You want to avoid making bubbles.

Leave for five minutes then strain carefully through the sieve into the jar.

Tilt the glass jar and carefully pour the surgical spirits down the side of the jar, at least as thick as the banana layer.  This will form a separate layer on top of the banana mixture.

Do not mix.

After five to ten minutes you will see a long, stringy substance appear in the top layer. This is the banana’s DNA.

You can use a tooth pick to lift and examine the DNA.


So what is happening?

The salt and washing up liquid break open the banana cells, releasing the DNA.

The DNA will not dissolve in the surgical spirits (or any alcohol) so it floats in this layer.


Here are a five fantastic facts about DNA…

5 Facts about DNA
5 Facts about DNA

The experiment described above is just a quick and simple method that I have used before but if you want something more scientific and a lot more fun… check out Cell Explorers! They do amazing school visits, for junior infants right up to secondary level students,  which I am sure would be of interest to teacher or parents making suggestions in their own schools. Run by Dr. Muriel Grenon and her wonderful team of students and graduates these activities are really top class!  Contact them by email at




Science blogger and writer; Owner of Dr. How's Science Wows; Mother of three junior scientists who have taught me that to be a great scientist you need to look at life through the eyes of a child!

4 thoughts on “Fun Friday – Five Fantastic Facts about DNA and how to extract DNA from a banana

    • August 20, 2014 at 7:35 pm

      Great, I used ethanol and isopropanol before, just check at your local pharmacy 🙂

  • August 17, 2014 at 11:54 pm

    Wow. You must really inspire your kids. It must be great for them to ask a question and actually get an answer. Loved this.
    tric kearney recently posted…To us.My Profile

    • August 18, 2014 at 7:50 pm

      Thanks Tric, the funny thing is that they so often ask their Dad instead of me, even the science questions. Sometimes I am bobbing up and down in the background just like Donkey at the end of the first Shrek movie, squeaking… “Oh me, me, pick me… I know this one”… 😉


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