These repository contains data and analysis code for the manuscript of the same name. This version has been updated for the accepted version of the paper. Details of individual files:Lee_et_al__sample_details.tsv - details of samples present in counts file below; updated for accepted version of the paperLee_et_al__counts.tsv - gRNA counts from both pilot and larger screens described in paperLee_et_al__normalisation_factors.tsv - normalisation factors used in analysis of the above countsinvivo_gecko_lee_et_al_v2.zip - contains code and other files associated with the analyses of the above data; figures in the paper can be reproduced from these files; v2 is updated for the accepted version of the paperNote: This repository does not contain the data or code for the simulation studies described in the paper, which is available upon reasonable request to the authors.