New findings solve human origins mystery

October 10, 2007

An extraordinary advance in human origins research reveals evidence of the emergence of the upright human body plan over 15 million years earlier than most experts have believed. More dramatically, the study confirms preliminary evidence that many early hominoid apes were most likely upright bipedal walkers sharing the basic body form of modern humans.

On October 10th, online, open-access journal PLoS ONE will publish the report based on research from Harvard University’s Museum of Comparative Zoology and from the Cedars Sinai Institute for Spinal Disorders that connects several recent fossil discoveries to older fossils finds that have eluded adequate explanation in the past.

Recent advances in the field of homeotic genetics together with a series of discoveries of hominoid fossils vertebrae now strongly suggest that a specific genetic change that generated the upright bipedal human body form may soon be identified. The various upright “hominiform” hominoids appear to share this morphogenetic innovation with modern humans. Homeotics concerns the embryological assembly program for midline repeating structures such as the human vertebral column and the insect body segments.

The report analyses changes in homeotic embryological assembly of the spine in more than 200 mammalian species across a 250 million year time scale. It identifies a series of modular changes in genetic assembly program that have taken place at the origin point of several major groups of mammals including the newly designated ‘hominiform’ hominoids that share the modern human body plan.

The critical event involves a dramatic embryological change unique to the human lineage that was not previously understood because the unusual human condition was viewed as “normal.”

“From an embryological point of view, what took place is literally breathtaking,” says Dr. Aaron Filler, a Harvard trained evolutionary biologist and a medical director at Cedars Sinai Medical Center’s Institute for Spinal Disorders. Dr. Filler is an expert in spinal biology and the author of three books about the spine – “Axial Character Seriation in Mammals” (BrownWalker 2007), “The Upright Ape” (New Page Books 2007), and “Do You Really Need Back Surgery” (Oxford University Press 2007).

In most vertebrates (including most mammals), he explains, the dividing plane between the front (ventral) part of the body and the back (dorsal) part is a “horizontal septum” that runs in front of the spinal canal. This is a fundamental aspect of animal architecture. A bizarre birth defect in what may have been the first direct human ancestor led to the “transposition” of the septum to a position behind the spinal cord in the lumbar region. Oddly enough, this configuration is more typical of invertebrates.

The mechanical effect of the transposition was to make horizontal or quadrupedal stance inefficient. “Any mammal with this set of changes would only be comfortable standing upright. I would envision this malformed young hominiform – the first true ancestral human – as standing upright from a young age while its siblings walked around on all fours.”

The earliest example of the transformed hominiform type of lumbar spine is found in Morotopithecus bishopi an extinct hominoid species that lived in Uganda more than 21 million years ago. “From a number of points of view,” Filler says, “humanity can be redefined as having its origin with Morotopithecus. This greatly demotes the importance of the bipedalism of Australopithecus species such as Lucy (Australopithecus afarensis) since we now know of four upright bipedal species that precede her, found from various time periods on out to Morotopithecus in the Early Miocene.”

Source: Public Library of Science

Explore further: A single gene mutation may have helped humans become optimal long-distance runners

Related Stories

What if robots never fell? Meet BALLU

November 18, 2016

(Tech Xplore)—Robots of the humanoid variety intrigue us, at times delight us, and at other times scare us silly. The thought of a robot malfunctioning, dropping its pizza tray or loading tool to turn around and murder ...

Recommended for you

Japan space robots start asteroid survey

September 22, 2018

A pair of robot rovers have landed on an asteroid and begun a survey, Japan's space agency said Saturday, as it conducts a mission aiming to shed light on the origins of the solar system.

First to red planet will become Martians: Canada astronaut

September 22, 2018

Astronauts traveling through space on the long trip to Mars will not have the usual backup from mission control on Earth and will need to think of themselves as Martians to survive, Canada's most famous spaceman half-jokingly ...

Ocean acidification may reduce sea scallop fisheries

September 21, 2018

Each year, fishermen harvest more than $500 million worth of Atlantic sea scallops from the waters off the east coast of the United States. A new model created by scientists at the Woods Hole Oceanographic Institution (WHOI), ...

New battery gobbles up carbon dioxide

September 21, 2018

A new type of battery developed by researchers at MIT could be made partly from carbon dioxide captured from power plants. Rather than attempting to convert carbon dioxide to specialized chemicals using metal catalysts, which ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

BobSage
2.8 / 5 (4) Oct 10, 2007
This reminds me of the humanzee. This was a chipanzee that had many human characteristics, including walking upright. There are many moving pictures of this creature showing it walking with a human gait. It was hypothesized that it was the offspring of a human and a chimp. But finally genetic tests revealed it was, indeed, a chimpanzee. Perhaps it resulted from the birth defect discussed in the article.

I think it's quite interesting that the upright carriage was accompanied by so many human characteristics, including, by the way, an inordinate interest in human females, to the exclusion of chimp females.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.