Science@Home. DIY DNA.

Huge apologies for the delay in posting this blog! This week has been super busy for me and it had plans to actually have a bit of a social life on the weekend so I couldn’t turn that down. But anyway, I thought it was time for a BRAND NEW feature! As I’m sure I’ve told you all before, a major goal for my blog is to make scientists look like ‘normal’ people and to make science in general more appealing and inclusive to everyone; from children, to parents, even to great-grandparents! So it got me thinking – there couldn’t be a better way of getting people interested in science than bringing the experiments out of the lab and into your homes!

If you can do it at home, how difficult can it be eh?

So, after my little science themed present for my sister this Christmas when I set about trying to keep science in the family it made me think that I can share some basic experiments with you guys that you can spend half term attempting – and get those little ones off their tablets and games consoles for an hour or so!


I’m a molecular biologist by trade so I do lots of experiments on cells and the microscopic things that are contained within cells – such as proteins, RNA and DNA. So, I found a way that you can extract your own DNA at home – and I cannot tell you how similar it is to the process I use in the lab to get the DNA out of my cells. Obviously there’s a lot more high tech equipment and posh chemicals but the reasoning behind adding each thing is exactly the same!

So, without further ado, I science in the lab but I would love it if you would join me and science@home! Let’s get looking at our DNA!



So these are the basic instructions you are going to need and I’ve taken some photos of what I’ve done at home too. So what do we need?

  • Saliva, glass, dish soap, pineapple juice, chilled alcohol (so make sure you’ve popped it in the freezer for a while before you start!), salt, a straw and a toothpick!

All stuff that you can easily get hold of right? It is that simple! Here’s the photo of the ingredients I used. Unfortunately I didn’t have a toothpick or a straw so I though I could try the end of a dental floss stick and just pour the alcohol in slowly!

But some great advice before starting any experiment is to read through all of the instructions before started so you have an idea of what you’re about to do!

Finished? Well, let’s begin!


Apologies about the gross photos coming up but it’s all in the name of science! 💪

Step 1 – Fill your glass a quarter full of saliva!

So, all living things are made up of cells, and inside every single one of those cells is some DNA. So, the instructions need your saliva because it will have some of your cheek cells in it and so we are going to try and get the DNA out of them!

Top tip: If you’re having trouble salivating then imagine you are sucking on a sweet! That might help!

Step 2 – Add a few drops of dish soap!

This step aims to break open the cells that are in your saliva and releases the contents of the cell – so your proteins, RNA and DNA are now free to roam! This is called the lysis step! It is a step we do in the lab too, but we use special lysis buffers to break open our cells!

Step 3 – Add a splash of pineapple juice!

So we have released all the proteins that are in your cells after breaking them up, but we don’t need those proteins. The pineapple juice, or you could use grapefruit juice instead, helps to break down those proteins that we don’t need anymore!

Step 4 – Add a pinch of salt!

The salt helps the DNA clump together which will make it a bit easier to see! This is another step that is very similar to what we do in the lab! We add a carrier molecule that helps us see the DNA – but obviously we don’t use salt! That would be far too cheap and easy for science :P!

Step 5 – Give it all a good mix!

Just make sure you give your glass a good swirl around and so everything is properly mixed together!


Step 6 – SLOWLY!!!! add the alcohol!

Fill up the rest of your glass or at least add the same volume of alcohol as mixture thats in your glass, but this has to be done slowly! The alcohol should sit in a layer on top of the mixture! This is what we call the precipitation step in the lab! The DNA is forced to move out of the mixture by adding the alcohol!



Step 7 – Use your toothpick to spool up the cloudy snot-like material that has formed in your glass!

That snot-like material you can see in the top layer or between the two layers is your DNA!! How easy was that right? I know its not that spectacular to look at but I think its pretty cool anyway 🙂



Please, please, please give it a go! It is so easy AND you might even have a bit of fun! I would love to see some photos of you getting stuck in to some science and something very similar to what I do in the lab some days! There are loads of other versions online if you want to look at the DNA of strawberries or peas for example, but please don’t go taking saliva from your pets and/or younger brothers and sisters etc.

As always, feel free to ask me any more questions about each experiment to answer those inevitable ‘mum/dad, why has that happened?’ questions!


Make sure you follow me and Soph talks Science for any updates and new blog posts on Facebook, Twitter and Instagram. Or if there is something you want to write about on my blog then please do get in contact with me!

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