C4B and cyclic hematopoiesis: Also aligning with previous reports, for CH overall and for most individual CH driver genes, we observed progressive shortening of telomere length with increasing clone size (any P = 1.3 × 10−14, β = −0.49 (−0.61 to −0.36)), probably reflecting accelerated telomere attrition with cell division in expanding clones (Supplementary Table 19).