A groundbreaking genetic study led by Chinese scientists has revealed that our ancient human ancestors teetered on the brink of extinction nearly a million years ago, with their population dwindling to approximately 1,280 individuals.
About the study: Published in the journal Science on Thursday, the study utilized a novel computer model called FitCoal to trace the genetic lineages of 3,154 present-day human genomes. The scientists found that approximately 98.7% of our human ancestors were lost during a population crash approximately 900,000 years ago. This critical phase persisted for a staggering 117,000 years.
A period of near-extinction: The dramatic decline in the ancient human population coincided with a period known as the mid-Pleistocene transition, marked by prolonged glacial periods and harsh climatic conditions.
This environmental upheaval, coupled with potential factors such as disease, natural disasters and limited food sources, may have pushed our ancestors to the brink of extinction. Researchers propose that shifts in climate favoring human habitation around 813,000 years ago could have played pivotal roles in the subsequent rapid population increase.
Findings’ significance: Researchers speculated that this decline correlates with a significant gap in the fossil record, raising questions about the emergence of a potential new hominin species — a common ancestor of modern humans and Neanderthals.
“The novel finding opens a new field in human evolution because it evokes many questions, such as the places where these individuals lived, how they overcame the catastrophic climate changes, and whether natural selection during the bottleneck has accelerated the evolution of [the] human brain,” said senior author Yi-Hsuan Pan, an evolutionary and functional genomicist at East China Normal University.
Further research needed: Nick Ashton, a curator at the British Museum, and Chris Stringer, a research leader in human evolution, acknowledged the study’s significance in a commentary published in the same journal. The two scientists, who were not involved in the study, stressed the need for further validation through archaeological and human fossil evidence.