We created mappability track per each base pair using 50bp simulated reads with GEM tools that are provided by ENCODE/CRG. We used GEM tools version "GEM-binaries-Linux-x86_64-20100419-003425". More information about how GEM tools creates mappability tracks can be found from: http://algorithms.cnag.cat/wiki/The_GEM_library AND http://genome.ucsc.edu/cgi-bin/hgTrackUi?g=wgEncodeMapability --> CRG Alignability Files under mappabilityIndicesPerChr-50bpReds/ contain one line per chromosome that is the mappability values of all bases for that chromosome without any separator.