Zeptomole level DNA detection!

Dear friends,

Deep apologies for the long time between posts. We've been making some big discoveries in the lab, applying for funding that could possibly set us up for the next 3 years and gaining interest from a couple of the big nature networks in the States (more in another post)!

In my last post I mentioned that we were trialing a couple of DNA amplification techniques to help us produce lots and lots of copies of DNA from extremely low quantities of snow leopard DNA....known as branched and hyper-branched rolling circle amplification. I've included a couple of pics of what that looks like below.

 Branched Rolling-circle Amplification (BRCA) produces lots of copies of the DNA you're targeting (like snow leopard)

Branched Rolling-circle Amplification (BRCA) produces lots of copies of the DNA you're targeting (like snow leopard)

 Hyper-branched Rolling-circle Amplification (HRCA)- produced even more copies of the DNA you're targeting!

Hyper-branched Rolling-circle Amplification (HRCA)- produced even more copies of the DNA you're targeting!

Frustratingly, it seemed that we weren't able to detect the levels of DNA we would expect with these techniques. But as it turns out, the gel we were using to see the amplified DNA was simply not sensitive enough to detect the low levels arising from the minute quantities we were starting out with. In other words, we were getting our reactions to work from quantities of snow leopard DNA so low that they couldnt be seen on a gel. Only by concentrating the DNA following the reaction were we then able to see this on the gel......and what this tells us has blown my mind!

 Those faint bands you can see above the very dark marker band shows that we are able to produce multiple copies of DNA from very low quantities of target DNA....0.0001 fmol = 100 zeptomoles = 10000 copies of DNA!!! 

Those faint bands you can see above the very dark marker band shows that we are able to produce multiple copies of DNA from very low quantities of target DNA....0.0001 fmol = 100 zeptomoles = 10000 copies of DNA!!! 

What this tells us in a nutshell is that we can detect down to 100 zeptomole of target, or snow leopard DNA which is 10000 copies of DNA! And the even better news is....this is just the start! By optimising the techniques and incorporating awesome nanotechnology that allows us to concentrate the DNA before we even run a reaction, we might be able to detect down to 100 or 10 copies of DNA. To put that into context......to detect snow leopard DNA in a scat sample, our device needs to be capable of detecting down to 10000 or 1000 copies.....with sensitivity like we're predicting, we may be able to detect DNA in water samples! 

As I now head back to Australia for 3 months after 2 years of perpetual winter, I'm feeling excited and optimistic about where this is heading. What started off as an ambitious idea is now turning into reality. And what I love most about it all, is that we're all achieving this together! Together we're creating a device that can hopefully be used in many aspects of conservation monitoring, for experts and non-experts alike.

Thank you for your continual support and belief in this idea!

xNat  

Natalie Schmitt