© Shanghai Institute of Nutrition and Health, CASRock art on a cliff illustrates how our human ancestors survived in the face of unknown danger. Next to it is the core forumula used by researchers to infer the bottleneck that occured close to 1 million years ago.
Humans might have almost gone extinct nearly 1 million years ago, with the world population hovering at only about 1,300 for more than 100,000 years, a new study finds.
This close call with extinction may have played a major role in the evolution of modern humans and their closest known extinct relatives, the thick-browed Neanderthals and the mysterious Denisovans, researchers added.
Previous research suggested that modern humans originated about 300,000 years ago in Africa. With so few fossils from around that time, much remains uncertain about how the human lineage evolved before modern humans emerged.
To learn more about the period near the evolution of modern humans, scientists investigated the genomes of more than 3,150 present-day modern humans from 10 African populations and 40 non-African ones. They developed a new analytical tool to deduce the size of the group making up the ancestors of modern humans by looking at the diversity of the genetic sequences seen in their descendants.
The genetic data suggest that between 813,000 and 930,00 years ago, the ancestors of modern humans experienced a severe "bottleneck," losing about 98.7% of its breeding population.
"Our ancestors experienced such a severe population bottleneck for a really long time that they faced a high risk of extinction," study co-lead author Wangjie Hu at the Icahn School of Medicine at Mount Sinai in New York City, told Live Science.
The researchers estimated the modern human breeding population numbered about 1,280 for about 117,000 years.
"The estimated population size for our ancestral lineage is tiny, and certainly would have brought them near to extinction," Chris Stringer, a paleoanthropologist at the Natural History Museum in London who was not involved in the new study, told Live Science.
The scientists noted this population crash coincided with severe cooling that resulted in the emergence of glaciers, a drop in ocean surface temperatures, and perhaps long droughts in Africa and Eurasia. Scientists still don't know how this climate change might have affected humans because human fossils and artifacts are relatively sparse during this time, perhaps because the population was so low.
© ScienceThis chart shows the timeline of the severe bottleneck and how many individuals likely existed during that time
If this last common ancestor lived during or soon after the bottleneck, the bottleneck may have played a role in splitting ancient human groups into modern humans, Neanderthals and Denisovans, Stringer explained. For instance, it might have split humans into tiny separate groups, and over time, differences between these groups would prove significant enough to divide these survivors into distinct populations — modern humans, Neanderthals and Denisovans, he said.
In addition, prior work suggested that about 900,000 to 740,000 years ago, two ancient chromosomes fused to form what is currently known as chromosome 2 in modern humans. Since this coincides with the bottleneck, these new findings suggest the near-eradication of humans may have some link with this major change in the human genome, the researchers noted.
"Since Neanderthals and Denisovans share this fusion with us, it must have occurred before our lineages split from each other," Stringer said.
Future research may apply this new analytical technique "to other genomic data, such as that of Neanderthals and Denisovans," Stringer said. This might reveal whether they similarly underwent major bottlenecks.
The study was published online Thursday (Aug. 31) in the Sept. 1 issue of the journal Science.
Charles Q. Choi is a contributing writer for Live Science and Space.com. He covers all things human origins and astronomy as well as physics, animals and general science topics. Charles has a Master of Arts degree from the University of Missouri-Columbia, School of Journalism and a Bachelor of Arts degree from the University of South Florida. Charles has visited every continent on Earth, drinking rancid yak butter tea in Lhasa, snorkeling with sea lions in the Galapagos and even climbing an iceberg in Antarctica.
Reader Comments
Consider the 4 base nucleotides that ALL organic forms are created from on Earth. To say humans are just transplants would be very odd then. Someone created DNA and seeded planets with it.... it didn't write itself.
CONSCIOUSNESS CREATES MATTER, Not the 'other way 'round'.
"I regard consciousness as fundamental. I regard matter as derivative from consciousness. We cannot get behind consciousness. Everything that we talk about, everything that we regard as existing, postulates consciousness." Max Planck, father of Quantum Physics
" The day science begins to study non-physical phenomena, it will make more progress in one decade than in all the previous centuries of its existence." Nikola Tesla
From the Seth series by Jane Roberts:
“Chemicals themselves will not give rise to consciousness or life. Your scientists will have to face the fact that consciousness comes first and evolves its own form… All cells in the body have a separate consciousness. There is a conscious cooperation between the cells in all the organs, and between the organs themselves… Molecules and atoms and even smaller particles have condensed consciousness. They form into cells and form an individual cellular consciousness. This combination results in a consciousness that is capable of much more experience and fulfillment than would be possible for the isolated atom or molecule alone. This goes on ad infinitum… to form the physical body mechanism. Even the lowest particle retains its individuality and its abilities [through this cooperation] are multiplied a millionfold.”
Physical matter makes consciousness effective within the three-dimensional reality. As individualized energy approaches your particular field, it expresses itself to the best of its ability within it. As energy approaches, it creates matter, first of all in an almost plastic fashion. But the creation is continuous like a beam or endless series of beams, at first weak as they are far off, then stronger, then weak again as they pass away. Matter of itself, however, is no more continuous, no more given to growth or age than is, say, the color yellow.”
Finally, my own statement to this issue;
Any True 'evolution' of Earth humans will involve the expansion of Consciousness, and our awareness of the Greater Reality, of which our PRESENT observable 'reality' is a Creation of our Collective Consciousness. This Creation of ours is itself but an infinitesimal sub-set of an Infinite number of realities and Probabilities brought into Being by a CONSCIOUSNESS beyond our capability to understand it. All That Is, is constantly evolving and growing - for the Creator made is such that Each Thought IS Energy and IS The Source of the Infinite Energy that forms All Reality.
The universe is FILLED with life and to think human life only exists on Earth is an Extremely constricted view, particularly given the acknowledgement by eminent scientists that 'extraterrestrials' do exist and have visited Earth.
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Some reading is in order...
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The events they are seeing is a genetic engineering standardization event (defragmenting the genetic hard drive for a species). Millions of members of a species have a specific set of genes set to a standard pattern giving the impression that there were only a few members of that species. This was not done by culling but by an update code to clean up that genetic space.
These “scientists” are not seeing a bottleneck they are seeing a species wide genetic reset.
Guessing that a critical genetic fork was terminated to prevent species fragmentation. Sometimes sub-populations exercise a genetic option that has to be reversed at a later date. Some genetic engineering is to reverse or reset genetic options which are now creating problems moving into the future.
Human genetic engineering based on “bottlenecks” always produce weak frail creatures like English Bulldogs. A key factor in genetic engineering is to keep the population numbers high. The higher the population the higher the number of genetic permutations that can resist diseases and maximize stability.
The population numbers that they are stating would have to be within a small geographic area. Inbreeding and extinction would occur just because of the physical separation of members in the group. Going 1000 kilometers to find an optimum genetic combination in a small population is not a realistic option.
The numbers given appear to represent the theoretical (gaming theory) minimum number of members for a genetic population under ideal conditions. The numbers given look like the population of the European Aristocracy and we know how bad that turned out genetically. (English twits breeding like rabbits.)
At low population levels open warfare between hominids was not a big problem.
A lot of experiments in hominid designs were running in parallel. But a civilization could only be built with one design.
Rather than choosing one design and losing the advantages of the other designs a reset was introduced which broke the hominid species barriers. After the reset the hominid species could interbreed. The resulting genetic hybrids were more robust than any single hominid species.
Next thing on the to do list: Creating a civilization robust enough to prevent being destroyed by interstellar and other asteroid impacts.
The devil will be played by American Science captured by oil company money. American science hid the existence of interstellar asteroids because they create the geological conditions for oil.
Because of this insanely criminal act, the money that the Americans should have spent on space infrastructure and asteroid defenses was spent enslaving the world.
America is endangering the payoff of a 500 million year investment by a galactic civilization.
America is about to experience the military equivalent of Galactic “Shock and Awe.”