Humans almost got extinct 100,000 years ago

Humans almost got extinct 100,000 years ago


04 September 2023

According to researchers who utilized a computer model to find a severe population bottleneck in the early Pleistocene 100,000 years ago, humanity struggled to exist during that time.

Between 813,000 and 930,000 years ago, an early human species experienced a bottleneck that reduced it to fewer than 1,300 breeding individuals. The problem continued for 117,000 years and corresponds to a chronological discrepancy in the African and Eurasian fossil records of early humans throughout that time. Science has just released the team's study on the bottleneck.

Population bottlenecks occur when the entire population of a species is drastically decreased, which results in a general decrease in genetic variation across the species. Population health may suffer as a result of genetic variety loss. Cloning and gene editing have made it possible for bioengineers to artificially create genetic variety in animal populations.

However, population bottlenecks are not necessarily a concern to populations. Take, for example, the flightless, infertile kkp of New Zealand or the severely endangered vaquita porpoise, which face more dangers from human-caused hazards and humanity as a whole than from limited genetic pools. Now it seems that a comparable population purge may have put an ancestor human species in danger.

In order to examine 3,154 modern genomes from 10 African and 40 non-African groups, the recent study team created a method dubbed the fast infinitesimal time coalescent process (FitCoal). In each of the 10 African communities, the scientists discovered proof of a "severe population bottleneck" that "brought the ancestral human population close to extinction," according to their report. The team suggests that climate changes may have caused the bottleneck.

The work was discussed in a Perspectives article written by Chris Stringer, a paleoanthropologist at the Natural History Museum in London, and Nick Ashton, an archaeologist at the British Museum.

Whatever caused the proposed bottleneck may have been limited in its effects on human populations outside the H. sapiens lineage, or its effects were short-lived,” Ashton and Stringer wrote. “This also implies that the cause of the bottleneck was unlikely to have been a major environmental event, such as severe global cooling, because this should have had a wide-ranging impact. Nevetherless, the provocative study of Hu et al. brings the vulnerability of early human populations into focus, with the implication that our evolutionary lineage was nearly eradicated.”

Since our species, Homo sapiens, did not first emerge in the fossil record until roughly 300,000 years ago, the projected population bottleneck would have had an impact on our ancestors. The Homo heidelbergensis fossils, which come from the bottleneck era, which lasted from 950,000 to 650,000 years ago, are among the few ones from Africa, the researchers note. According to the scientists, the bottleneck "possibly marks a speciation event leading to the emergence of the [last common ancestor] shared by Denisovans, Neanderthals, and modern humans."

Although other studies indicate that the last common ancestor lived earlier, Stringer and Ashton point out that if the bottleneck happened with the severity predicted by the researchers, it might have had a profound impact on the evolution of life.

Understanding how ancient human populations migrated around the world and interbred with other populations, including other hominin species, is becoming easier thanks to genetic modeling.

For instance, population bottlenecks in more recent history have provided clues about how particular groups were affected by climate shifts. The spread of humanity around the world may be better understood by comparing ancient DNA with present DNA from various cultures.

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