DNMT3A and cyclic hematopoiesis: This is particularly surprising with respect to DNMT3A and TET2, whereby mutations with opposing effects on DNA methylation promote similar increases in HSC fitness and/or “stemness.” Additionally, there are key differences between these CH subtypes, with DNMT3A dominating CH in early life and TET2-CH becomes increasingly common later in life, overtaking DNMT3A-CH by the eighth decade (80, 81).