Tuesday 3 September 2013

Finding your way around NGS sample prep

I'm often asked which sample prep method a user should consider for their experiments. In my lab we use a lot of Illumina TruSeq kits; we've tried other methods, and do use Rubicon's Thruplex, but Ilumina's end-to-end support is useful in a medium sized core facility. And the kits work!

I wanted to illustrate the fact that Illumina sample preps share many steps in their protocols to demonstrate that once you've mastered one protocol, you can easily move onto another. The map of sample prep below is my first try at that illustration. You can see a higher resolution image here.

Explaining how the kits work always takes time and I have always thought a strength of the Illumina technology is the flexibility given by the core of sample prep: end repair, ligate adapters & PCR. Users can think creatively about what they do to their DNA (or cDNA) before starting or during the prep to come up with novel techniques. Stranded RNA-seq, bisulfite sequencing, RRBS, exome capture are just a few of the methods developed by users of Illumina technology. Hopefully the image above shows how similar things really are with those key steps clearly highlighted as large "interchanges", along with PCR and qPCR & Bioanlayser for QT/QC.

The above image borrows heavily from the London underground maps developed by Harry Beck in 1931. Most of the Illumina protocols are listed and I've included Thruplex on its own network for comparison. I'm aiming to add more detail for some of the different RNA-seq protocols at some point as well as bisulfite sequencing. I'm also thinking about how this might be extended to include details on suggested sequencing depth; lines for Human genome vs CNV-seq or DGE vs splicing.

Let me know what you think.

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  1. I love this. Visual representation of workflows in such a crip manner is beautiful, nice work!

  2. impressive! really cool!

  3. Excellent illustration. Have you thought about adding cleanup steps or would that get too messy? In addition to other RNA library prep methods, there are a few new DNA preps which combine ER and Adenylation or use rolling amplification techniques to start with low input DNA. This map could get big !

  4. Really nice illustration!
    Would it make sense to add the duration for each step? Might help with deciding what to do...


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