Differential cell fates of muscle stem cells are accompanied by symmetric segregation of canonical H3 histones in vivo

Stem cells are maintained through symmetric or asymmetric cell divisions. While various mechanisms initiate asymmetric cell fates during mitosis, possible epigenetic control of this process has emerged recently. The asymmetrical distribution of a canonical histone H3 variant during mitosis in fly germline has suggested a role for partitioning old and new nucleosomes in asymmetric cell fates. Here, we provide resources for single cell assays and show the asymmetric segregation of transcription factors along with old and new DNA in mouse muscle stem cells ex vivo and in vivo . However, these differential fate outcomes contrast with a symmetric distribution of the canonical H3.1 vertebrate variant. These findings point to different evolutionary mechanisms operating in fly germline stem cells and vertebrate somatic stem cells to mitigate epigenetic regulation of asymmetric cell fates.