Smoke and natural selection

Twenty years ago I listed several questions about evolution and medicine that I hoped someone would work on. The first was, “Has exposure to smoke shaped human adaptations?” The amazingly comprehensive answer is provided in “The Exposome in Human Evolution: From Dust to Diesel” a new article by Finch and Trumble in the Quarterly Review of Biology. The article is unfortunately behind a paywall, but Carl Zimmer provides a wonderful overview in the NY Times.

Abstract: Global exposures to air pollution and cigarette smoke are novel in human evolutionary history and are associated with at least 12 million premature deaths per year. We investigate the history of the human exposome for relationships between novel environmental toxins and genetic changes during human evolution in six phases. Phase I: With increased walking on savannas, early human ancestors inhaled crustal dust, fecal aerosols, and spores; carrion scavenging introduced new infectious pathogens. Phase II: Domestic fire exposed early Homo to novel toxins from smoke and cooking. Phases III and IV: Neolithic to preindustrial Homo sapiens incurred infectious pathogens from domestic animals and dense communities with limited sanitation. Phase V: Industrialization introduced novel toxins from fossil fuels, industrial chemicals, and tobacco at the same time infectious pathogens were diminishing. Thereby, pathogen-driven causes of mortality were replaced by chronic diseases driven by sterile inflammogens, exogenous and endogenous. Phase VI: Considers future health during global warming with increased air pollution and infections. We hypothesize that adaptation to some ancient toxins persists in genetic variations associated with inflammation and longevity.