A new method of estimating ancient population size reveals a severe bottleneck in human populations that nearly wiped out the potential for humanity as we know it today.
Unexplained gaps in African and Eurasian fossil records may be explained thanks to research team It consists of researchers from China, Italy, and the United States. Using a new method called FitCoal (Fast Infinitesimal Time Coalescence Process), researchers were able to accurately determine demographic inferences using 3,154 modern human genome sequences. These findings indicate that our early human ancestors experienced a severe, long-term bottleneck in which around 1,280 breeding individuals were able to sustain a population for around 117,000 years. This research has revealed several aspects of our early to mid-Pleistocene ancestry, but many more questions remain to be answered after this information is revealed.
FitCoal methodology
In this study, a large number of genome sequences were analyzed. But “the fact that FitCoal can detect severe ancient bottlenecks with even a small amount of sequence is a breakthrough,” said lead author Yun-Yun, a theoretical population geneticist at the University of Texas Health Science Center in Houston. Xin Fu said.
Researchers publish their findings online. science August 31, 2023 (ET). Using FitCoal to calculate the likelihood of current genome sequences, we found that our early human ancestors experienced an extreme loss of life and therefore a loss of genetic diversity.
Interpreting the fossil gap
“The gap in the African and Eurasian fossil records can be chronologically explained by this bottleneck in the Early Stone Age, which coincides with this proposed period of significant loss of fossil evidence,” said the lead author. Giorgio Manzi, an anthropologist at Sapienza University of Rome, says: The reasons suggested for this decline in human ancestral populations are primarily due to climate. Glacial events during this period cause temperature changes, severe droughts, and loss of other living organisms. seedmay have been used as a food source by human ancestors.
Genetic diversity and human evolution
The impact of this bottleneck is staggering. We know today that an estimated 65.85% of current genetic diversity may have been lost due to this bottleneck during the early to mid-Pleistocene, resulting in a long period of minimal breeding population. threatened humankind. However, this bottleneck appears to have contributed to a speciation event in which the two ancestral chromosomes converged to form what is now known as chromosome 2 in modern humans. This information may reveal the last common ancestor of Denisovans, Neanderthals, and modern humans (homo sapiens).
discover new questions
We all know that once a question is answered, more questions arise.
“This new discovery raises many questions, including where these people lived, how they overcame catastrophic climate change, and whether natural selection during bottlenecks accelerated the evolution of the human brain. , it opens a new field in human evolution,” said Yi-Hsuan Pan, senior author of Evolutionary Functional Genomics at East China Normal University (ECNU).
Now that they have reason to believe that an ancestral conflict occurred between 930,000 and 813,000 years ago, researchers continue to investigate to find answers to these questions. can reveal how people survive in difficult and potentially dangerous conditions. Control of fire and changes to a climate more suitable for human life may have contributed to the subsequent rapid population growth around 813,000 years ago.
“These discoveries are just the beginning. Future goals, leveraging this knowledge, aim to paint a more complete picture of human evolution during the early-to-mid Pleistocene transition, thereby “We will continue to unravel the mysteries of our early ancestry and evolution,” said senior author Li Hai-Peng. Theoretical population geneticist and computational biologist at the Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences (SINH-CAS).
Reference: “Genomic inference of severe bottlenecks in humans during the early-to-middle Pleistocene transition” Wangjie Hu, Ziqian Hao, Pengyuan Du, Fabio Di Vincenzo, Giorgio Manzi, Jialong Cui, Yun-Xin Fu, Yi- Written by Hsuan Pan, Haipeng Li, August 31, 2023, science.
DOI: 10.1126/science.abq7487
The study was co-led by Haipeng Li from SINH-CAS and Yi-Hsuan Pan from ECNU. Their collaborators, Fabio Di Vincenzo of the University of Florence, Jojo Manzi of Sapienza University of Rome, and Yun-Shin Fu of the University of Texas Health Science Center in Houston, contributed important findings to the study. made a contribution. The first authors of this study are Wangjie Hu and Ziqian Hao, who were SINH-CAS and his ECNU students/interns. They are currently affiliated with the Icahn School of Medicine at Mount Sinai, Shandong First Medical University and Shandong Province. medical academy, Each. Pengyuan Du of SINH-CAS and his colleague Jialong Cui of ECNU also contributed to this research.