Restriction site Associated DNA Sequencing (RAD-Seq) is a fractional genome sequencing strategy, designed to interrogate anywhere from 0.1 to 10% of a selected genome. Now, depending upon the bead ratio with samples we separate fraction of DNA to be sequenced in RAD.
So, for which step do you using the Ampure Beads XP? I am working with ddRADSeq and we use the Ampure Beads XP for the purification step as suggested in Peterson et al. 2012. You can also use the beads for size selection, but I never did that before.