According to a study published in The Journals of Gerontology, a DNA sequence variation allows certain individuals to live long lives, even if they expose themselves to unnecessary harm (such as cigarette smoke).
The researchers studied the small proportion of smokers who don’t experience early mortality, and discovered that they shared in common a network of SNPs (a naturally occurring DNA variation) that is strongly linked with longevity.
The study’s lead author, Morgan Levine, explains the function of the SNPs:
‘We identified a set of genetic markers that together seem to promote longevity. What’s more, many of these markers are in pathways that were discovered to be important for ageing and lifespan in animal models. There is evidence that these genes may facilitate lifespan extension by increasing cellular maintenance and repair.
‘Therefore, even though some individuals are exposed to high levels of biological stressors, like those found in cigarette smoke, their bodies may be better set up to cope with and repair the damage.’
The study’s findings suggest that in some cases genetics may play a greater part in longevity than environmental factors. This would suggest that people who survive a lifetime of smoking have been lucky, not to have beaten the odds, but to belong to a biologically distinct group.
The researchers believe that the same gene variations are an important factor in cancer prevention. Those who took part in the study were found to have an almost 11 per cent lower cancer prevalence.