'Population Bottleneck': With 98.7% Ancestors Lost, Study Claims This Is How Humanity Nearly Went 'Extinct'

Based on a recent study, ancient humanity nearly vanished when there were just 1,280 reproducing people on the planet 900,000 years ago. Additionally, the population of our prehistoric ancestors remained this low for roughly 117,000 years.

A team of scientists from China, Italy, and the United States built a new computer model on which the analysis, published in Science on August 31, was based. 3,154 modern human genomes' worth of genetic data were used in the statistical procedure. The study estimates that 98.7% of our ancestors have been lost.

According to the researchers, a gap in the fossil record may have caused the rise of a new hominin species that was the ancestor of Neanderthals and modern humans, or Homo sapiens, and the population crash.

The Thin Line Between Life And Extinction: A Scientific Revelation

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According to senior author Yi-Hsuan Pan, an evolutionary and functional genomics researcher at East China Normal University, "The novel finding opens a new field in human evolution because it evokes many questions, such as the locations where these people lived, how they survived the catastrophic climate changes, and whether natural selection during the bottleneck has accelerated the evolution of the human brain."

The research team hypothesized that the mid-Pleistocene shift, also known as the population bottleneck, was accompanied by significant climatic changes. Temperatures dropped, and the climate became more arid as glacial periods grew longer and more intense.

Additionally, the scientists hypothesized that the suppression of fire and a temperature change that made conditions more favourable for human life may have aided in a later, fast population expansion that occurred around 813,000 years ago.

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According to the authors, the earliest evidence of cooking food using fire is 780,000 years ago in modern-day Israel. Although ancient DNA has completely changed how we think about past populations, the oldest human DNA is about 400,000 years old.

To estimate the number of populations at particular historical junctures, the computer model extensively uses the wealth of information on genetic diversity across time seen in contemporary human genomes.

The research team used 40 non-African and 10 African populations' genetic sequences.

A Study That Is 'Provocative'

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In a commentary on the findings published in the same journal, Nick Ashton, curator of the Paleolithic collections at the British Museum, and Chris Stringer, research leader in human evolution at the Natural History Museum in London, called the work "provocative."

According to the two academics who were not involved in the study, the study "brought the vulnerability of early human populations into focus."

With fossils from that period discovered in what is now China, Kenya, Ethiopia, Italy, Spain, and the United Kingdom, Ashton and Stringer claimed that the fossil record, despite being sparse, did demonstrate that early human species lived in and outside of Africa between 813,000 and 930,000 years ago ¡ª during the time of the proposed population collapse.

"Whatever caused the proposed bottleneck may have been limited in its effects on human populations outside the Homo sapiens lineage or its effects were short-lived," the two researchers wrote in their comments.

They continued that the projected bottleneck needs to be evaluated in light of historical and archaeological data.

What do you think about it? Do let us know in the comments.

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