New Study Reveals Devastating Population Bottleneck in Human Ancestors Nearly a Million Years Ago
Nearly a million years ago, a catastrophic event nearly wiped out humanity’s ancestors, according to a new study. Genomic data from 3,154 modern humans suggests that the population was reduced from approximately 100,000 to just 1,280 breeding individuals around 900,000 years ago. This jaw-dropping population decline of 98.7 percent lasted 117,000 years and could have brought humanity to the brink of extinction.
The study, led by geneticists Haipeng Li of the Chinese Academy of Sciences and Yi-Hsuan Pan of East China Normal University, provides an explanation for a curious gap in the human fossil record in the Pleistocene. Anthropologist Giorgio Manzi of Sapienza University of Rome suggests that the bottleneck in the Early Stone Age coincides with the proposed time period of significant loss of fossil evidence.
Population bottlenecks, which are significant reductions in a group’s numbers, are not uncommon. When a species is devastated by events such as war, famine, or climate crisis, the resulting drop in genetic diversity can be traced through the progeny of the survivors. This is how researchers have identified a human population bottleneck in the Northern Hemisphere around 7,000 years ago.
However, the further back in time researchers look, the more challenging it becomes to unravel these past events. To overcome this challenge, the research team developed a new method called the fast infinitesimal time coalescent process (FitCoal). This method allowed them to analyze the genomic data of 3,154 people from around the world and trace how gene lineages have diverged over time.
The results of the study showed a significant population bottleneck from around 930,000 to 813,000 years ago, resulting in a current genetic diversity loss of up to 65.85 percent. While the exact cause of the bottleneck remains uncertain, one major event that could have played a role is the Mid-Pleistocene Transition, during which Earth’s glaciation cycles dramatically changed. The climate turmoil during this period may have produced conditions that were not favorable for human populations, leading to famine and conflict that further reduced population numbers.
The study also revealed that the bottleneck contributed to the fusion of two chromosomes to form chromosome 2 in humans. Humans have 23 pairs of chromosomes, while all other hominids alive today, including the great apes, have 24. The formation of chromosome 2 seems to have been a speciation event that set humans on a different evolutionary path.
The findings of this study open up new avenues for research in human evolution. The researchers hope to uncover more about the places where these individuals lived, how they survived the catastrophic climate changes, and whether natural selection during the bottleneck accelerated the evolution of the human brain.
“This novel finding opens a new field in human evolution because it evokes many questions,” says Yi-Hsuan Pan. “Future goals with this knowledge aim to paint a more complete picture of human evolution during this Early to Middle Pleistocene transition period, which will continue to unravel the mystery of early human ancestry and evolution.”
The research has been published in the journal Science.
What were the long-term consequences of the significant loss of genetic diversity resulting from the population bottleneck nearly a million years ago
Rchers in this study used genomic data from modern humans to track the population bottleneck nearly a million years ago.
The researchers analyzed the genomes of 3,154 modern humans from diverse populations around the world. By examining patterns of genetic diversity and estimating the size of the ancestral human population, they were able to piece together the story of a devastating population bottleneck.
Their findings revealed that around 900,000 years ago, the human population faced a catastrophic event that reduced their numbers to just 1,280 breeding individuals. This represented a shocking decline of 98.7 percent from an estimated population of approximately 100,000.
The population decline lasted for an astonishing 117,000 years, putting humanity on the brink of extinction. This period coincides with a gap in the human fossil record during the Pleistocene, providing an explanation for the lack of fossil evidence from this time period.
Population bottlenecks have occurred throughout history and can have lasting effects on a species. In this case, the significant loss of genetic diversity resulting from the bottleneck nearly a million years ago likely had long-term consequences for human evolution and adaptation.
Understanding these population bottlenecks and their effects on genetic diversity is crucial for studying human evolution. By examining genomic data from modern humans, researchers can shed light on our ancient past and the challenges our ancestors faced.
While unraveling events from such a distant time period is challenging, this study demonstrates the power of genomic data in uncovering the mysteries of human history. It highlights the resilience of our ancestors and the remarkable journey that has led to the diversity of human populations we see today.
This sounds like a fascinating journey into our past! Can’t wait to learn more about our ancestors.