Estimating the chance of acquiring a specific driver mutation within any single HSC by 60 years of age. Calculations use estimates provided by Lee-Six et al⁴⁴  for the total HSC population size (between 44 000 and 215 000 cells) and the rate of mutation acquisition in individual HSCs (estimated to be 1 mutation every 3 weeks, or 17 mutations per year). The total number of base pairs in the human genome is approximated at 3 billion.