Off topic:Rnaseq Library Prep Help: How To Clean Up High Molecular Weight Aftifact?

Question

[jonsleepy]

Hi All, I created some amplified cDNA and we notice some artifact above 10,000 on the Bioanalyzer plots; see:

https://docs.google.com/file/d/0B_2H...it?usp=sharing

It's most profound on the first sample, but is apparent in all 3.

I'm considering using the first part of a dual-SPRI bead size-selection procedure, where I use a small volume of beads to bind only the large stuff, and then recover my sample from the supernatant.

But I'm not sure of a good volume of beads to use.. Thinking it should be much lower than 1x the volume of the sample in water. But how low? 0.2x? Higher? Lower?

Thanks for any help! Jon