TIL 70,000 years ago a volcanic eruption killed many humans, leaving only 1,000 human alive in the whole word. This created a population bottleneck which vastly reduced diversity in human genetics.

The Toba eruption (sometimes called the Toba supereruption or the Youngest Toba eruption) was a supervolcano eruption that occurred around 74,000 years ago at the site of present-day Lake Toba in Sumatra, Indonesia. It is one of Earth's largest known explosive eruptions. The Toba catastrophe theory holds that this event caused a severe global volcanic winter of six to ten years and contributed to a 1,000-year-long cooling episode, leading to a genetic bottleneck in humans.A number of genetic studies have revealed that 50,000 years ago, the human ancestor population greatly expanded from only a few thousand individuals. Science journalist Ann Gibbons has posited that the low population size was caused by the Toba eruption. Geologist Michael R. Rampino of New York University and volcanologist Stephen Self of the University of Hawaiʻi at Mānoa have supported her suggestion. In 1998, the bottleneck theory was further developed by anthropologist Stanley...