Ancient ape ‘Gigantopithecus' was a distant relative of orangutans

A three-metre tall, 600 kg ape called Gigantopithecus blacki is an ancestor of the modern-day orangutan, scientists have recently proven. This giant ape inhabited Southeast Asia until around 300,000 years ago. 

The link between Gigantopithecus and the orangutan was made by a team of scientists from University of Copenhagen’s Globe Institute, using proteins extracted from dental enamel from 1.9 million year old Gigantopithecus fossils found in southern China in 1935. 

With no known evidence of DNA from Gigantopithecus, it’s been almost impossible to establish where this creature fits within the complex evolutionary history of primates and hominids (‘great apes’), until now.

Thanks to the new technique from an emerging field called proteomics, researchers have finally been able to extract molecular information from the fossilised Gigantopithecus teeth and compare this with a database of known hominids proteins. 

Proteomics, in basic terms, is more or less reverse-engineering DNA by looking at proteins preserved in teeth. As each protein is made up of amino acids, and because each amino acid is encoded by a three-letter DNA sequence, researchers can produce snippets of ancient DNA by analysing these proteins. Scientists applied this technique to a 1.9 million year old Gigantopithecus molar tooth, found in a Chuifeng cave in China.

The fossil tooth confirmed to scientists that the largest known ape in the world is an ancestor of the modern-day orangutan. The orangutan is now classified as a critically endangered species, as it can only be found in the wild on the islands of Sumatra and Borneo. 

It is now understood that the Gigantopithecus appeared at the beginning of the ancestral line of orangutans.

Judging from the cavities in the fossil teeth, experts conclude that Gigantopithecus, which became extinct about 300,000 years ago for reasons that are not completely understood, was probably herbivorous (plant-based), after examining fossils of microscopic plants found in some of the teeth.

Postdoctoral researcher at the Globe institute Frido Welker explained: "Our data, for the first time, provides independent molecular evidence that the closest living relative of Gigantopithecus is the modern orangutan. 

“Until now, it has only been possible to retrieve genetic information from up to 10,000-year-old fossils in warm, humid areas - as this kind of environment is usually inhospitable for extensive preservation.”

The success of the proteomic technique has big implications for the future of paleoanthropology.

Many of the fossilised remains of ancient hominids come from tropical and subtropical areas, such as East Africa, southern Africa and Indonesia. Within these climates there is very little chance that viable DNA could have survived. The proteomic technique changes things.

Palaeoanthropologist and study co-author Wei Wang, from Shandong University, China, said: “The evolutionary lineages of orangutans and Gigantopithecus separated about 12 million years ago, and the creature's origin and evolution has puzzled palaeoanthropologists for more than half a century, meaning this discovery provides a significant scientific breakthrough.”

Experts hope future research can benefit from proteomic techniques to extract information from other fossils, perhaps including species in the human evolutionary lineage.

The scientists, though pleased with their findings as this sheds light on Gigantopithecus’s origins say that it still doesn’t tell us very much about what this huge ape looked like or how it would have behaved, meaning there is still much more work to be done. 

Reference: Frido Welker,Tomas Marques-Bonet, Enrico Cappellini et. al. “Enamel proteome shows that Gigantopithecus was an early diverging pongine”. Nature (13 November 2019). DOI: https://doi.org/10.1038/s41586-019-1728-8