What is the Hayflick limit?

About Hayflick limit:

• It refers to the maximum number of times a cell can divide.
• It's named after scientist Leonard Hayflick, who discovered this phenomenon.
• The limit plays a crucial role in aging and the development of age-related diseases.
• Hayflick found that cells go through three phases.
  • The first is rapid, healthy cell division.
  • In the second phase, mitosis slows. In the third stage, senescence, cells stop dividing entirely.
  • They remain alive for a time after they stop dividing, but sometime after cellular division ends, cells do a particularly disturbing thing: Essentially, they commit suicide.
  • Once a cell reaches the end of its life span, it undergoes a programmed cellular death called apoptosis.
• Hayflick’s discovery got further weight after researchers in the 1970s discovered Telomeres.
• Telomeres are repetitive DNA sequences at the very end of these strands, meant to protect the chromosome.
• Crucially, with each cell division, these telomeres get slightly shorter. Eventually, the telomere loss reaches a critical point at which cell division ends.
• That said, while shortening telomeres is related to aging, the exact relationship between telomere length and lifespan remains unclear.