 Abstract the generation of conditional alleles using CISPR technology is still challenging. Here, we introduce a short conditional intron SCON-189 BP that enables the rapid generation of conditional alleles via one-step zygote injection. In this study, a total of 13 SCON mouse lines were successfully generated by two different laboratories. SCON has conditional intronic functions in various vertebrate species, and its target insertion is as simple as CISPR-CAS-9 mediated gene tagging. This article was authored by Susie and Sam Wu, Hitak Lee, Rika Sepakani, and others.