A new international study, which involved the participation of Sapienza and the University of Florence for Italy, has identified a dramatic demographic crisis in human populations that occurred less than a million years ago, specifically at the end of the Early Pleistocene. This crisis has been linked to the drastic climatic changes of that period.
This event would have reduced the population of our ancestors to a number comparable to species at risk of extinction. However, it was crucial for the emergence of Homo heidelbergensis, the ancestral species at the origins of Homo sapiens.
The results of the study have been published in the journal Science, and it involved a group of Chinese and Italian researchers, including experts from the Chinese Academy of Sciences, East China Normal University in Shanghai, the University of Texas, Sapienza University of Rome, and the University of Florence.
Using an innovative bioinformatic method called “FitCoal,” the researchers examined the complete genomes of 3,154 present-day individuals from 50 different human populations. They combined these data with paleoenvironmental (climate) and paleoanthropological (fossil) information to trace back to prehistoric periods before the appearance of our species, as explained by Prof. Haipeng Li, who coordinated the research.
The study’s results revealed that between 930 and 813 thousand years ago, the population of our ancestors decreased by approximately 98.7%, leaving only around 1,300 fertile individuals. This number is comparable to species at risk of extinction, such as modern-day pandas. This phenomenon, known as a genetic “bottleneck,” was most likely due to the drastic climatic changes during the so-called “Middle Pleistocene Transition.”