The greatest ape — an extinct, half-ton monster — now has its place on our family tree
Gigantopithecus might have been 3m tall and 600kg
Ancient protein recovered from fossils of a mysterious extinct giant ape that lived in southeast Asia millions of years ago shows that it is most closely related to the modern day orangutan. This breakthrough technique could be a new way to understand the evolutionary history of many species.
A giant among apes
The fossil record of the extinct giant ape, Gigantopithecus blacki, is extremely limited. There are only a few lower jaw bones, but fortunately lots of teeth. The fossils were first found in a cave in southern China in 1935 and dated at 1.9 million years old. Based on these limited fossils, though, paleontologists estimate it could have reached tremendous size - 3 metres tall and up to 600 kilograms.
However, because the fossil remains of Gigantopithecus are so limited, it's been difficult to tell what it's related to and how it fits on the ape family tree. Ancient DNA was not an option because the species disappeared about 100,000 years ago and no ancient DNA beyond 10,000 years old had ever been successfully retrieved in a subtropical climate such as that of southern China.
Tell-tale teeth
With the the retrieval of ancient DNA ruled out, Enrico Cappellini and his colleagues from the University of Copenhagen's Faculty of Health and Medical Sciences tried a new technique: sequencing preserved protein from Gigantopithecus' dental enamel. This was done using state of the art mass spectrometry and paleoproteomics.
Protein sequences, like those of DNA, accumulate changes over evolutionary time. By looking at the sequence in the preserved protein from the dental enamel, and comparing it to protein from living apes, Cappellini and his team were able to reconstruct the extinct ape's evolutionary relationship to living great apes.
The closest living relation turned out to be the orangutan. They also determined that the lineages of Gigantopithecus and orangutan diverged about 12 million years ago.
Possibilities for reconstructing human evolutionary lineage
Their success in sequencing ancient proteins for Gigantopithecus has Cappellini excited about the possibility of applying this technique to better understand human evolution. The hope is that evolutionary relationships between our species and extinct lineages like australopithecus or homo erectus could be much better understood.
Fossil evidence of our ancestors, homo sapiens, are most commonly found in subtropical regions, just like Gigantopithecus, and so ancient DNA can often not be found. By looking at more robust preserved proteins, we could learn a great deal about the evolutionary line that led to modern humans.
