Fireside Chat, Interview
The bacteria that shaped history: Yersinia pestis – David Reich
- A quantitative analysis suggests a single pathogen caused between one-quarter and one-half of deaths in Western Eurasia over the 4,000 to 5,000-year historical window.
- The pathogen is hypothesized to have originated from steppe rodents, potentially providing slightly greater protection to steppe populations than to European farming societies around 5,000 years ago.
- High mortality rates from the pathogen may have triggered population disorganization similar to disruptions in the Americas, creating an opportunity for less densely spread migrants to enter Europe.
- This mass mortality is expected to have disrupted established lifestyles and facilitated a radical transformation in European ancestry between 5,000 and 4,500 years ago, potentially through the mechanism of replacing hunter-gatherer and farmer populations entirely across Europe.
- The text posits that the replacement of populations occurred a second time, allowing modernity to emerge subsequently, though the pathogen is estimated to be not the primary cause of deaths in the New World despite its role there.
- The transcript asserts that while the Black Death contributed to the end of seniorial responsibilities by inflating wages and creating inflation in the medieval period, other Roman plagues were definitely not caused by Yersinia.
- Robert Allen's theory is presented as a potential link wherein population reduction drove up wages in Britain and forced machinery development, thereby contributing to the Industrial Revolution.
- The plague of Justinian is documented as the final event that killed off the Roman Empire, distinguishing it from the earlier pathogen discussed in the context of steppe migrations.