Saddle shaped DNA Library?

[Squall]

Hi all,

Has anyone seen a saddle shaped library following sample preparation using Nextera? Attached picture.

Or would anyone have any thoughts on the cause?

Thanks!

[nucacidhunter]

I have not seen one like this. I wonder if the Bioanalyser trace is cleaned up PCR product from three different libraries or dilutions of one. There are few possible causes:
1) tagmentation reaction set up and incubation temperature
2) efficiency of tagmentation clean up
3) quantity and quality of input DNA
4) PCR cycling