Retention frequency of the Nile tilapia hybrid cell lines. The hybrid cell lines are numbered from 1 to 381 on the X axis. Presence/absence of 48 microsatellite markers spread all over the tilapia genome  was estimated by PCR determination. Their retention frequency per clone is presented on the Y axis. The 190 hybrid cell lines selected on quantitative and qualitative criteria that constitutes the tilapia RH panel are in green.