A new study using a new genetic analysis technique has revealed that human ancestors in Africa were dangerously close to extinction around 900,000 years ago. The study, published in the journal Science, shows a significant decline in the population of our ancestors long before Homo sapiens emerged. The breeding population dwindled to just 1,280 individuals and did not recover for another 117,000 years.
Haipeng Li, a population geneticist at the University of Chinese Academy of Sciences in Beijing and co-leader of the study, claims that about 98.7% of human ancestors died during this period. He suggests that the scarcity of fossils from Africa and Eurasia between 950,000 and 650,000 years ago can be explained by this population bottleneck.
Nick Ashton, an archaeologist at the British Museum in London who wrote a related look at the study, finds the small size of the extant population intriguing. He suggests that for such a small group to survive, it was necessary to occupy a localized area with strong social cohesion. In addition, he emphasizes the remarkable longevity of this small group, suggesting that it required a stable environment with sufficient resources and minimal stressors.
To uncover this ancient history, researchers have developed innovative tools, as traditional methods have been limited in their ability to study early human ancestors. While genome sequencing provided insights into population size after the emergence of modern humans, the research team developed a technique that allowed them to analyze earlier human ancestors. By constructing a complex gene family tree, they were able to study specific branches with greater precision and identify significant evolutionary events.
Serena Tucci, an anthropologist at Yale University, praises this groundbreaking work for shedding light on the population dynamics of early human ancestors. She notes that previous knowledge in this area has been limited due to methodological constraints and difficulties in obtaining ancient DNA data.
The researchers’ methodology focused on the period from 800,000 to 1 million years ago, known as the transition period between the Early and Middle Pleistocene. This era was characterized by dramatic climate change and more intense glacial cycles. Africa experienced prolonged droughts that may have wiped out human ancestors and led to the emergence of new species of humans. Over time, these species may have evolved into the last common ancestor of modern humans, as well as our extinct relatives Denisovans and Neanderthals.
This study provides a glimpse into our ancient past and reveals the challenges our ancestors faced and what they needed to survive. It emphasizes the importance of a stable environment and resources for the development and continuation of the human race.