Fig. 2

Optimizing haESC culture and enrichment systems. a During daily cell culture, haESCs undergo severe self-diploidization thus preventing their application in genetics. b Although haESC concentrations can be enriched using the Hoechst 33342 sorting method, the effect of Hoechst 33342 is toxic and does great harm to haESCs. c Since haploid ESCs are half to two-thirds the size of diploid ESCs, they can be sorted according to their physical parameters. However, this strategy is subjective and difficult to judge. d An optimized culturing system which allows for the perpetual maintenance of haESCs is needed. FACS fluorescence-activated cell sorting, haESC haploid embryonic stem cell