Do I inherit my life expectancy from my parents?
You do not inherit a fixed life expectancy, but you do inherit a genetic susceptibility that partly shapes your risk of certain diseases. Your own choices, and especially whether you smoke, have a major influence on that.
Life expectancy is partly linked to your genes, but the two available claims focus specifically on lung cancer as an example of how a parent's lifespan and disease susceptibility are connected. There is a clear negative genetic link: people with a genetic tendency toward shorter parental lifespan also have a higher genetic vulnerability to lung cancer. That connection operates at the level of shared DNA, not as a direct passing on of a 'short life' gene.
A father's history of lung cancer is also statistically associated with a higher lung cancer risk in his children. This points to shared genetic susceptibility, but smoking and other lifestyle factors also play a role and are difficult to separate cleanly from the genetic contribution in this kind of research.
What this means in practice: you do not inherit a fixed expiry date from your parents. What you do inherit is a susceptibility that partly determines how vulnerable you are to certain diseases, such as lung cancer, that can shorten life expectancy. Whether that susceptibility actually leads to illness depends strongly on your own behaviour and environment. Smoking is by far the most important changeable factor when it comes to lung cancer.
This answer is based on two claims from a single study that examined genetic links between parental lifespan, paternal lung cancer, and the genetic risk of lung cancer in children. The researchers measured associations at the DNA level, not cause-and-effect relationships. No direct study on the heritability of life expectancy as a whole was available; the evidence is limited to lung cancer as a specific example.
Do my stem cells run out as I get older?
Stem cells gradually become depleted and function less well as we get older. How quickly this happens varies from person to person and is still very much an active area of research.
Can you counteract DNA damage from ageing through your lifestyle?
Quitting smoking, exercising regularly and eating plenty of vegetables demonstrably reduce DNA damage; antioxidant supplements are unlikely to help with this.
Why do your telomeres get shorter as you age?
Telomeres shorten because the copying process during cell division cannot fully reproduce the ends of chromosomes, and the repair enzyme telomerase is switched off in adult body cells. Stress and oxidative damage can accelerate that process further, but the fundamental mechanism is unavoidable as long as cells divide.
What do zombie cells do to your ageing?
Zombie cells accumulate as you age and accelerate ageing through inflammatory signals; how to tackle them is promising but still very much under investigation.
Can you read your disease risks from your DNA?
DNA research shows which diseases appear more often in your genetic profile, but rarely predicts whether you will actually develop them. Use a result as a starting point for a conversation with your doctor, not as a final verdict.
What do mitochondrial mutations mean for how quickly you age?
Mitochondrial mutations likely contribute to ageing, but exactly how large that contribution is, and through which mechanism, has not yet been definitively established. At this time, there are no proven interventions that can be taken on this basis.