Because in essence what it means is you can take a cell, which is a pluripotent stem cell, which is like a skier at the top of a mountain, and those two skiers become two pluripotent stem cells, four, eight, 16, after 16 divisions that those cells have to differentiate.
なぜならこれが意味するのは 細胞を一つ採取し それが 多分化能な幹細胞だとします たとえて言えばスキーヤーが山頂にいて 二人のスキーヤーが二つの多分化能幹細胞となり 4 8 16 へと分裂し 16 分裂以降は 多くなり過ぎなので 細胞は分化を始めます