In the US we can expect to live to about 77 years old on average. Is this the best we can do? How much can we extend our lifespan? The oldest person on record lived to be 122 years old.
To answer these questions, we need to understand what happens to our bodies as we age. Are we programmed to live a certain number of years or do we wear out over time? These are two main theories of why we live as long as we do.
In the first, the idea is that our genes determine how long we live. We have a gene or some genes that tell our body how long it will live. If you could change that particular gene, we could live longer.
The second theory is that over time, our body and our DNA get damaged until we can no longer function properly. The idea here is that how long we last is really just a consequence of small changes in our DNA. These changes add up until the total amount of damage is too much to bear and we die.
It matters which theory is right, as it will determine how to push the limits of aging. For example, if how old we live is in our genes, then to increase our lifespan we may be able some day to change those genes. If on the other hand, our final age is based on the accumulated damage of a lifetime, then we could try to minimize that damage to live a longer life.
Which theory is right? Probably reality is a combination of these two ideas (plus some others we won't discuss). In the past decade, scientists have found evidence to support both theories.
Work in animals, in particular in worms, has shown that mutating certain genes can increase lifespan about 4-fold. For humans, that would translate to about 300 years old! These results would seem to support that there are genes that determine how long we live.
Of course, if those genes are involved in fixing the damage that comes with aging, then the data would support the second model. In the well-known human disease called Werner's syndrome, a mutated gene causes people to get older at a faster pace. The gene that is mutated is thought to be involved in DNA maintenance.
Other work shows that eating less increases how long animals will live. Although the reason for the increase in lifespan is unclear at this point, scientists have proposed that it has to do with decreasing DNA and cellular damage. Still other work suggests that cells can divide only a certain number of times. This is because of DNA at the end of chromosomes called telomeres that get shorter with each division. When they run out, the cell dies.
As you can see, trying to understand aging is a challenge. However, many scientists are fascinated by the questions of aging and the research is progressing fast. The following article is an example of the latest research on aging. The authors of the article use the mouse as a model to test the importance of mitochondrial DNA in aging.
by Sophie Candille
To answer these questions, we need to understand what happens to our bodies as we age. Are we programmed to live a certain number of years or do we wear out over time? These are two main theories of why we live as long as we do.
In the first, the idea is that our genes determine how long we live. We have a gene or some genes that tell our body how long it will live. If you could change that particular gene, we could live longer.
The second theory is that over time, our body and our DNA get damaged until we can no longer function properly. The idea here is that how long we last is really just a consequence of small changes in our DNA. These changes add up until the total amount of damage is too much to bear and we die.
It matters which theory is right, as it will determine how to push the limits of aging. For example, if how old we live is in our genes, then to increase our lifespan we may be able some day to change those genes. If on the other hand, our final age is based on the accumulated damage of a lifetime, then we could try to minimize that damage to live a longer life.
Which theory is right? Probably reality is a combination of these two ideas (plus some others we won't discuss). In the past decade, scientists have found evidence to support both theories.
Work in animals, in particular in worms, has shown that mutating certain genes can increase lifespan about 4-fold. For humans, that would translate to about 300 years old! These results would seem to support that there are genes that determine how long we live.
Of course, if those genes are involved in fixing the damage that comes with aging, then the data would support the second model. In the well-known human disease called Werner's syndrome, a mutated gene causes people to get older at a faster pace. The gene that is mutated is thought to be involved in DNA maintenance.
Other work shows that eating less increases how long animals will live. Although the reason for the increase in lifespan is unclear at this point, scientists have proposed that it has to do with decreasing DNA and cellular damage. Still other work suggests that cells can divide only a certain number of times. This is because of DNA at the end of chromosomes called telomeres that get shorter with each division. When they run out, the cell dies.
As you can see, trying to understand aging is a challenge. However, many scientists are fascinated by the questions of aging and the research is progressing fast. The following article is an example of the latest research on aging. The authors of the article use the mouse as a model to test the importance of mitochondrial DNA in aging.
by Sophie Candille
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