The prehistoric ancestors of mankind almost disappeared completely due to the demographic collapse

The demographic collapse has nearly wiped out human prehistoric ancestors, scientists say. Genomics analyzes show that at least 800,000 years ago, the number of breeding individuals dropped to just 1,300.

According to scientists, the prehistoric ancestors of man were close to destruction as a result of a serious evolutionary “bottleneck” about 800-900 thousand years ago, writes The Guardian.

A genomic analysis of more than 3,000 living humans has shown that the total population of our ancestors plummeted to about 1,280 breeding individuals in about 117,000 years. Scientists believe that an extreme climate event may have created a bottleneck that nearly wiped out our lineage.

“The numbers from our study are consistent with those of species that are currently threatened with extinction,” says Professor Giorgio Manzi, an anthropologist at the Sapienza University of Rome and senior author of the study.

However, Manzi and his colleagues believe that bottleneck existential pressure may have triggered the emergence of a new species, Homo heidelbergensis, which some believe is the common ancestor of modern humans and our “cousins” the Neanderthals and Denisovans. It is believed that Homo sapiens appeared about 300 thousand years ago.

“We are lucky to have survived, but … we know from evolutionary biology that the emergence of a new species can occur in small, isolated populations,” says Professor Manzi.

Professor Chris Stringer, head of human origins at the Natural History Museum in London, who was not involved in the study, said: “This is an extraordinary period of time. It’s great that we made it through. For a population of this size, one adverse climatic event, an epidemic, a volcanic eruption, is enough, and you are gone!”

This decline in population appears to coincide with major changes in global climate that have made glaciations into long-term events, a decrease in sea surface temperatures, and a possible extended period of drought in Africa and Eurasia. The team behind the work said the time window also coincides with a relatively empty period in the fossil record.

“We know that between about 900,000 and 600,000 years ago, the fossil record in Africa was very sparse, if not almost non-existent, while both before and after we have more fossil evidence,” emphasizes Professor Manzi. “The same can be said about Eurasia: for example, in Europe we had a species known as Homo antecessor about 800,000 years ago, and then there was nothing for about 200,000 years.”

However, Professor Stringer notes that there is no strong evidence for a global “gap” in the fossil record of early humans, raising the possibility that what caused the “bottleneck” was a more local phenomenon. “Perhaps this population bottleneck is stuck in some area of ​​Africa surrounded by desert,” he suggests.

The paper, published in the journal Science, analyzed the genomic sequences of 3,154 people alive today from 10 African and 40 non-African populations. By studying the different versions of genes in a population, one can approximate the date when certain genes first appeared – the more time that has passed, the more likely it is that different variants of a gene will appear. By assessing the frequency with which genes have appeared over time, scientists can gain insight into how ancestral populations have grown and shrank over time.

The analysis found evidence of a bottleneck in all African populations, but only a weak signal of this event was found in 40 non-African populations. This is likely because the ancestors of people of non-African descent actually experienced a later demographic decline during the out-of-Africa migration, which is expected to mask an earlier event.

This time roughly coincides with when the last common ancestor is believed to have roamed the Earth with the Neanderthals and another ancient human species, the Denisovans. The scientists now want to find out if the genetic patterns of these ancient relatives are evidence of the same bottleneck, which could provide new insight into when, where and why the species diverged.