FACS purified MuSCs were immediately proccessed for ATACseq sample preparation. Between 10.000 and 20.000 FACS sorted cells were used for ATAC Library preparation using Tn5 Transposase from Nextera DNA Sample Preparation Kit (Illumina). Cell pellet was resuspended in 50µl PBS annd mixed with 25µl TD-Buffer, 2.5µl Tn5, 0.5µl 10% NP-40 and 22µl water. Cell/Tn5 mixture was incubeated at 37°C for 30min with occasional snap mixing. Transposase treatment was followed by 30min incubation at 50°C together with 500mM EDTA pH8.0 for optimal recovery of digested DNA fragments. For neutralisation of EDTA 100µl of 50mM MgCl2 was added followed by purification of the DNA fragments by MinElute PCR Purification Kit (Qiagen). Aplification of Library together with Indexing was performed as described elsewere (Transposition of native chromatin for fast and sensitive epigenomic profiling of open chromatin, DNA-binding proteins and nucleosome position. (2013) Jason D Buenrostro, Paul G Giresi, Lisa C Zaba, Howard Y Chang & William J Greenleaf. Nature Methods. doi:10.1038/nmeth.2688). Libraries were mixed in equimolar ratios and sequenced on NextSeq500 platform using V2 chemistry.