Pandemic: Tracking Contagions, from Cholera to Coronaviruses and Beyond

by Sonia Shah

Grasping this rather counterintuitive notion requires a brief digression into what’s called the “selfish gene theory” of evolution. The basic idea is that genes—or, rather, the genome, which is the entire complement of genes in a given individual—are the movers and shakers of evolution. The genome consists of long twisted molecules of DNA (or RNA), which are carried around in each of our cells, bits of which (the genes) provide instructions for a wide range of biological traits, from eye color to nose shape to the sound of one’s voice. According to the selfish gene theory, all of evolution can be boiled down to their machinations. Some genes, by dictating or “coding” for traits that help them spread more widely, become dominant. Others, which code for traits that are useless or harmful to their own dissemination, die out.