Unearthing Skepticism: Reevaluating Claims of Near Extinction Among Human Ancestors

Is it possible that the fate of today's global population of eight billion people hinged upon the resilience of just 1,280 human ancestors who nearly faced extinction around 900,000 years ago? This intriguing possibility has recently surfaced in a study that employs advanced genetic analysis modeling to shed light on the precarious existence of our ancient forebears, who endured the brink of annihilation for roughly 120,000 years.

Nonetheless, it's important to note that not all scientists are in unanimous agreement with this startling claim. Some experts in population genetics have expressed skepticism about the precision of the study's findings. They argue that estimating population changes dating back so far in time is an incredibly intricate task, and similar methods in the past have not uncovered such a significant population crash.

Understanding the lives of our ancient relatives who lived hundreds of thousands of years ago is exceptionally challenging due to the scarcity of DNA-containing fossils from that era. 

Nevertheless, advances in genome sequencing have provided researchers with the ability to analyze genetic mutations in modern humans and employ computer models that work backward in time to infer historical population changes.The study, which was recently published in the journal Science, examined the genomes of over 3,150 contemporary humans. Led by a Chinese research team, the study developed a computational model that estimated the population of breeding human ancestors dwindled to around 1,280 individuals approximately 930,000 years ago.

The study's co-author, Haipeng Li of the Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, stated that "About 98.7 percent of human ancestors were lost" at the onset of this bottleneck, emphasizing the near-extinction event that our ancestors faced. This bottleneck is thought to have persisted until 813,000 years ago. Subsequently, there was a population surge, potentially triggered by a warming climate and mastery of fire.One intriguing aspect of this research is the suggestion that inbreeding during the bottleneck could explain why humans exhibit lower genetic diversity compared to many other species. 

Additionally, it's posited that this population squeeze might have played a role in the distinct evolutionary paths of Neanderthals, Denisovans, and modern humans, all believed to have branched off from a common ancestor around that time.However, some archaeologists have raised questions about this theory, citing the discovery of fossils dating from the same period in various locations such as Kenya, Ethiopia, Europe, and China. These findings imply that our ancestors might have been more widespread than the bottleneck scenario suggests.In response to these objections, the study's authors argue that the Eurasian and East Asian hominins from that era may not have significantly contributed to the ancestry of modern humans. "The ancient small population is the ancestor of all modern humans. Otherwise, we would not carry the traces in our DNA," emphasized Li. 

This study opens a window into the complex and often mysterious history of our species, offering tantalizing clues about our ancient past and the forces that shaped us into who we are today.