Hayflick, his limit, and cellular ageing

Almost 40 years ago, Leonard Hayflick discovered that cultured normal human cells have limited capacity to divide, after which they become senescent - a phenomenon now known as the 'Hayflick limit'. Hayflick's findings were s trongly challenged at the time, and continue to be questioned in a few circ les, but his achievements have enabled others to make considerable progress towards understanding and manipulating the molecular mechanisms of ageing.