Ancestors of Modern Humans Faced Near-Extinction Event 900,000 Years Ago, Study Reveals
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Ancestors of Modern Humans Faced Near-Extinction Event 900,000 Years Ago, Study Reveals
Utilizing a novel methodology involving modern genetic data, researchers propose that this critical period saw the survival of pre-human individuals in a remarkably small population of just 1,280.
A recent study published in the journal Science has unveiled a remarkable and startling chapter in the history of human evolution. The research, led by population geneticist Haipeng Li from the University of Chinese Academy of Sciences in Beijing, sheds light on a critical period around 900,000 years ago when our ancient human ancestors in Africa teetered on the edge of extinction.
The study presents a groundbreaking analysis that uncovers a significant reduction in the population of our ancestors, Homo erectus, long before the emergence of our species, Homo sapiens. The findings indicate that the number of breeding individuals dwindled to an astonishingly low count of just 1,280, and this population bottleneck persisted for about 117,000 years before expanding once again.
Haipeng Li emphasizes the magnitude of this event, stating that "about 98.7% of human ancestors were lost" during this challenging time. This remarkable study offers a critical piece of the puzzle for understanding the complex evolutionary journey of early hominins and highlights the remarkable resilience that allowed a small group to survive under dire circumstances.
Nick Ashton, an archaeologist from the British Museum, underscores the significance of the study's findings. He suggests that the localized survival of such a tiny population implies a tight-knit social structure and a stable environment that facilitated their survival. Astonishingly, this population of early humans endured for a staggering period of over 117,000 years, suggesting an environment with adequate resources and limited external stresses.
To unravel this ancient mystery, the research team developed innovative methodologies that combined insights from genome sequencing with population genetics. By constructing an intricate genetic family tree, the researchers managed to peer deep into the past, exploring the finer branches of our ancestral lineage. This technique spotlighted the period between 800,000 and one million years ago, a time of climatic turmoil and significant environmental change.
During the Early-Middle Pleistocene transition, characterized by dramatic shifts in climate and lengthening glacial cycles, Africa faced prolonged periods of drought. These harsh conditions likely played a pivotal role in the near-extinction of our early human ancestors, driving new human species to emerge, adapting to these new challenges.
Around 813,000 years ago, a significant rebound in the pre-human population began. However, the factors that enabled their survival and eventual resurgence remain shrouded in mystery. Ziqian Hao, a co-author of the study, acknowledges the enigmatic nature of this period but emphasizes its importance. The bottleneck event likely had a profound impact on human genetic diversity, potentially influencing key aspects of our species, including brain size and various genetic traits.
Yet, while this study presents a groundbreaking perspective on our ancient past, some researchers are urging caution and additional evidence. Ashton raises questions about the scale of the bottleneck, suggesting that it might have been more regionally confined rather than a global phenomenon.
In conclusion, this study offers a fascinating glimpse into a crucial period of our evolutionary history. The precarious survival of a small population of early human ancestors during a tumultuous time paints a vivid picture of our species' remarkable tenacity and adaptability in the face of adversity. As researchers continue to unlock the mysteries of our past, the story of our ancient ancestors becomes all the more captivating and complex.
Wangjie Hu et al., Genomic inference of a severe human bottleneck during the Early to Middle Pleistocene transition. Science 381, 979-984 (2023). DOI:10.1126/science.abq7487