Question: Why is the age limit around 120?

Lucy McGowan answered on 19 May 2020: last edited 18 May 2020 11:14 pm

Ageing is a hot topic at the moment as it underpins many diseases. Many scientists are trying to uncover the biological or genetic “switches” for ageing and youthfulness. As we age our cells get worse at dividing and replenishing themselves. Each time a cell divides into two, it must copy all of the DNA in the cell without errors. The older we get and the more we are exposed to damaging environmental factors like poor diet, smoking or sun exposure, the more error prone our DNA becomes. A mistake made in DNA replication is called a mutation. Sometimes mutations make no difference, sometimes they are good but sometimes they are bad. Bad mutations can cause diseases; since getting older makes DNA replication more error-prone, it limits our lifespan. We also have little caps on the end of our chromosomes called telomeres. Telomeres protect the chromosomes during DNA replication and cell division. Each time a cell divides, the telomeres get a little bit shorter. Eventually, the telomeres can’t protect the chromosome anymore. This is what scientists refer to as “ageing” but at a molecular and cellular level. This ageing can cause cells to die and make us more unhealthy. As we get older, the shortening of telomeres happens in more and more cells in the body. Lots of scientists are looking at how certain lifestyles and certain genes can prevent telomere destruction and ageing! Heres some more info on telomeres: https://www.tasciences.com/what-is-a-telomere.html