On average, most humans around the world and throughout history who died from natural causes, have passed away around the age of 80 years old. Humanity has been wondering for years why does death usually come around this age for humans, and why do other animals and creatures have a much shorter or in some cases longer life span?
A new study from the Wellcome Sanger Institute in Cambridge suggests that the speed at which genetic mutations occur could determine why each species has a specific lifespan. Genetic mutations usually occur due to DNA errors which damage the DNA in the long term.
The study has discovered in different species of animals that by slowing down their rate of DNA mutations, they live longer. The speed at which DNA mutations occur does not depend on the size of an organism, but on the simple genetics by that, they have been created.
For example, previous studies which tried to solve this mystery blamed life span on the size of an organism. The bigger the creature, the more energy it has to consume as it has to replace more cells as the genes deteriorate with time. The new study argues that this is not the case, as a mole rat has a life span of around 25 years and a giraffe has a life span of around 24 years. The giraffe is arguably 1000 times bigger than the mole rat, yet they both live the same amount of time.
This shows that size does not matter, what matters is the speed at which the DNA mutates. When scientists checked the mutation rates of both the animals mentioned above, they were almost similar. The mole rat suffers 93 mutations a year and the giraffe 99 mutations per year.
Dr. Alex Cagan the lead author of this study says that this opens the door for humanity to better understand the aging process and how this could be manipulated in the future to hopefully make the lifespan of humans longer.
“But the most exciting aspect of the study has to be finding that lifespan is inversely proportional to the somatic mutation rate. This suggests that somatic mutations may play a role in aging.” (Quote by Dr. Alex Cagan)
To place this study into better perspective, a mice lives around 3.7 years and suffers 796 mutations per year. The average human lifespan (only taking into consideration death from natural causes) is around 83.6 years. The reason why we as humans have a much longer lifespan is that we only suffer 47 mutations per year. If a mice was to suffer the same amount of mutations per year, it would live as long as us based on the math behind the theory.
If scientists will find a way in the future to slow the rate of mutations we suffer per year, we would be living much longer. Besides the ability of our bodies to live a certain period of time, it also comes down to the type of lifestyle we live and the respect we all have for our own physical as well as mental health.