Search results
Results from the WOW.Com Content Network
Cellular senescence is a phenomenon characterized by the cessation of cell division. [1] [2] [3] ... [15] (see DNA damage theory of aging). ...
The typical normal human fetal cell will divide between 50 and 70 times before experiencing senescence. As the cell divides, the telomeres on the ends of chromosomes shorten. The Hayflick limit is the limit on cell replication imposed by the shortening of telomeres with each division. This end stage is known as cellular senescence.
Senescence (/ s ɪ ˈ n ɛ s ə n s /) or biological aging is the gradual deterioration of functional characteristics in living organisms. Whole organism senescence involves an increase in death rates or a decrease in fecundity with increasing age, at least in the later part of an organism's life cycle.
This is called cellular senescence. Senescence can be induced by several factors, including telomere shortening, [37] DNA damage [38] and stress. Since the immune system is programmed to seek out and eliminate senescent cells, [39] it might be that senescence is one way for the body to rid itself of cells damaged beyond repair.
The two theories; non-adaptive, and adaptive, are used to explain the evolution of senescence, which is the decline in reproduction with age. [8] The non-adaptive theory assumes that the evolutionary deterioration of human age occurs as a result of accumulation of deleterious mutations in the germline. [8]
While telomeres play an important role in cellular senescence, the intricate biological details of telomeres still require further investigation. [24] The complex interactions between telomeres, different proteins and the cellular environment must be fully understood in order to develop precise and safe interventions to change it. [25]
Therefore, a greater investment in growth and reproduction would result in reduced investment in DNA repair maintenance, leading to increased cellular damage, shortened telomeres, accumulation of mutations, compromised stem cells, and ultimately, senescence. Although many models, both animal and human, have appeared to support this theory ...
APT was first proposed in a 1952 paper on the evolutionary theory of ageing by Peter Medawar and developed further in a paper by George C. Williams in 1957 [1] as an explanation for senescence. [2] Pleiotropy is the phenomenon where a single gene influences more than one phenotypic trait in an organism.