How many times does mitosis typically occur in mammalian cells before cell death?

In mammalian cells, mitosis generally occurs around 20 to 50 times before the cell reaches its limit of division, often referred to as the Hayflick limit. This limit is defined by the number of times a somatic (body) cell can divide before cell division stops.

This phenomenon is largely due to the gradual shortening of telomeres, which are protective caps on the ends of chromosomes that diminish with each division. Once these telomeres shorten to a critical length, the cell can no longer divide, leading to senescence or programmed cell death.

Therefore, the range of 20 to 50 divisions reflects the typical lifespan of dividing mammalian somatic cells, aligning with the understanding of cellular aging and replication limits in cultured cells. This limit can vary among different types of cells and their biological functions, but the cited range is a widely accepted estimate in cellular biology.