Do genes determine your death?

A common question about ageing is whether or not genes have an important role to play; in other words does it matter who your ancestors are and does that have much bearing on how long you will live? Obviously, if you inherit a gene for a fatal illness it does. If you inherit a disorder which makes it difficult for your body to perform at optimum function, that too will play a part in how long you survive. Your family history will tell you this.

But the question remains: given a first rate set of genes, can you control when you will die, even in part, or is it already pre-programmed? Obviously it is an important point because if you can influence the outcome of an inherited health trait, or override it altogether, then truly your health and survival is in your own hands. The external or environmental factors that we bring to bear on issues can compensate for any destructive genetic material we have been provided with. The question is: can it be done?

The answer is slightly complicated but interesting. It's fashionable today, of course, to believe that everything is in the genes. But genes don't always show up. The gene for blue eyes, for instance, is subordinate to the gene for brown eyes. So if you get one of each (one from your mother and one from your father), the brown eyes will win. This is called a dominant gene (blue eyes are a recessive gene). But then it is found that sometimes even the dominant gene doesn't show up as it should. So scientists are beginning to talk of gene "expression" (whether it will come into play or not).

Many external factors will influence whether or not a gene expresses itself fully or partially. So really all this is saying that environmental factors are very important and genes are not the be-all-and-end-all, though science continues to peddle this silly story. Let us make this clearer by inventing an example: supposing that mother eating a lot of garlic while pregnant will suppress the brown eye gene (this is not true, we made it up to illustrate a point!). Which then controls the eye colour, genes or the garlic-rich diet? The answer is that is doesn't matter; because you can't change the genes, but you have the choice of eating garlic or not. So only the garlic is important. Do you see?

Where does this leave us in anti-ageing science? There are many genetic factors read more