The controversial Toba catastrophe theory , presented in the late 1990s to early 2000s , suggested that a bottleneck of the human population occurred c. 70,000 years ago , proposing that the human population was reduced to perhaps 10,000 – 30,000 individuals when the Toba supervolcano in Indonesia erupted and triggered a major environmental change . Parallel bottlenecks were proposed to exist among chimpanzees , gorillas , rhesus macaques , orangutans and tigers . The hypothesis was based on geological evidence of sudden climate change and on coalescence evidence of some genes ( including mitochondrial DNA , Y-chromosome DNA and some nuclear genes ) and the relatively low level of genetic variation in humans
Toba catastrophe theory
Toba catastrophe theory
Population bottleneck