In Rudolf Jaenisch's Cell 2013 Paper (One-Step Generation of Mice Carrying Mutations in Multiple Genes by CRISPR/Cas-Mediated Genome Engineering), they just mentioned that they injected 126bp single strand DNA into embryos at the HDR template, but they didn't provide any other information about the purity or the amount?
Or why there must be 126bp?
Could anybody help me out?