The genetic predisposition to suffering from multiple sclerosis (MS) is closely linked to historical migration patterns, and to our ancestors’ lifestyles. Specifically, MS is linked to the genetic contributions made by nomadic populations who reached Western Europe 5000 years ago from the Siberian Steppe.
Human genomes vary by 0.1%, and this difference is often the result of responses to environmental pressures. When faced with epidemic diseases, for instance, natural selection means the genetic variants that provide individual resistance to pathogens are the ones that survive. These markers are, in terms of population genetics, “positively selected”.
