It has long been appreciated that Retinoic Acid (RA) is critical for initiating entry in to meiosis, but clearly this is not the sole trigger for the progression from spermatogonia to spermatocytes. We have recently used single cell RNAseq (scRNAseq) to uncover key genes that are required for this transition (Grive et al, 2019). Through this analysis, we have identified candidate genes to study further and are currently pursuing CRISPR targeting strategies to define the role of each gene in initiating this differentiation process.