Even 20 years ago around 80 per cent of cancers seemed to be due to environmental factors that could be reduced. Now, a staggering number of synthetic chemicals are being used in, or produced by, industry and agricultural activities, and the worry is that many of these can alter sections of our DNA directly or indirectly.
For example, some can wind up in the foods that we consume, and cooking at high temperatures can even create novel chemicals which are a hazard to our DNA.
Of course, the other great shift in our post-industrial environment is global warming, and the radiation from this can also harm our genes. We have a problem arising from the sun’s ultraviolet radiation; while less energetic than nuclear radiation for example, it can still damage our DNA.
There are also several threats that derive from the environmental factors of our lifestyles. Evidence shows lifestyle issues such as tobacco smoke, dietary deficiencies, and possibly consumption of some pesticides may obstruct the critical mechanisms of DNA.
For example, one mechanism is the process of ‘epigenetic tagging’ that normally performs the function of switching genes off or on, during our development and aging.
In part, this process involves the attachment, or detachment, of small chemical tags to certain DNA components, crucially in regions of our DNA where they are essential to how specific genes perform.
Several human disorders can be caused by the malfunctioning of this process, resulting in intellectual disabilities and atypical physical characteristics.
With these in mind, it may seem like our genes and the environment are hopelessly entwined with questions about how we survived this long.
Interestingly, alongside the Earth’s ozone layer which protects us from much of the sun’s damaging radiation, research has recently demonstrated that our cells are equipped with an impressive array of enzymes that can neutralise many toxic effects of hazardous chemicals too.
In even better news, we seem to have several different enzyme systems which can facilitate the repair of different types of DNA damage. These are also helped by diets filled with fresh fruits and vegetables that have the potential to supply antioxidants to alleviate possible health challenges.
So where do we stand? Our war against our environment will never be won. The enemy, environment-induced gene change, occasionally scrapes through, with any DNA damage not repaired possibly being passed down through genetics and preluding the development of different types of cancer.
The point becoming apparent now is that many of our life experiences, and those of our forebears due to their environment, can have a real and lasting impact on our lives through being embedded in our DNA.
Roy Burdon is professor emeritus at the University of Strathclyde where he was chairman of the department of bioscience, and a fellow of the Royal Society of Edinburgh. This article expresses his own views. The RSE is Scotland's national academy, bringing great minds together to contribute to the social, cultural and economic well-being of Scotland. Find out more at rse.org.uk and @RoyalSocEd