Mutational bias in spermatogonia impacts the anatomy of regulatory sites in the human genome

ATAC-Seq reports local chromatin accessibility and provides a snapshot of active regulatory regions and genomic regions occupied by DNA-binding proteins in a given tissue. We used ATAC-Seq to identify open chromatin sites in FGFR3-positive spermatogonial cells isolated from dissociated human testicular samples. FGFR3 is most highly expressed in self-renewing spermatogonial stem cells, with low expression also being detected in early differentiating spermatogonia; its expression thus overlaps with the onset of PRDM9 expression in pre-meiotic spermatogonia. Open chromatin in FGFR3-positive cells was identified using standard peak detection analysis with MACS2 software.