STANDING at least 2.5 metres tall, Gigantopithecus lived in the forests of South-East Asia between 2 million and 300,000 years ago. It was larger than any living great ape, but all we have found of it so far are teeth and fragments from jawbones, so we know little about its appearance or behaviour.
Now we have been able to glimpse its family tree, which suggests it split from orangutan-like cousins around 11 million years ago.
To create the family tree, Frido Welker at the University of Copenhagen in Denmark and his colleagues studied a 1.9-million-year-old Gigantopithecus tooth discovered in southern China.
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The climate in this region is subtropical, with an average temperature of around 20掳C. In such warm and wet conditions, DNA soon breaks down, so it isn鈥檛 possible to read Gigantopithecus鈥榮 genome. Instead, the team extracted proteins from its tooth enamel, as these are more durable.
鈥淭his is the big breakthrough of this paper,鈥� says Katerina Douka of the Max Planck Institute for the Science of Human History in Jena, Germany. DNA is normally used for studies like these, but proteins are a promising alternative in cases where this isn鈥檛 possible. 鈥淣o one so far has ever managed to get DNA older than 8000 to 10,000 years old from that part of the world.鈥�
The researchers compared the Gigantopithecus proteins to those of other apes. This allowed them to draw a family tree that suggests Gigantopithecus鈥榮 closest living relatives are orangutans (Nature, ).
This was long suspected, says Russell Ciochon at the University of Iowa. 鈥淲e expect Gigantopithecus to be more closely related to the orangutans than the African apes,鈥� he says.
Welker鈥檚 study suggests the ancestors of Gigantopithecus split from those of orangutans 10 to 12 million years ago, a time when apes were diversifying.
This means much of the ape鈥檚 evolutionary history remains unknown, as the oldest Gigantopithecus remains found so far are only 2 million years old.
The study is a significant step forward for the use of ancient proteins. It demonstrates that it is possible to obtain proteins from 2-million-year-old teeth in warm climates. Proteins may last even longer in fossils in more temperate regions.
Indeed, other researchers have managed to extract proteins from found in the Arctic.
It is unclear just how long such proteins can be preserved. Some researchers claim to have extracted proteins from 66-million-year-old dinosaur fossils. However, many believe those proteins are bacterial contamination.
Douka is optimistic about whether ancient proteins can last this long. She says it is possible dinosaur proteins are preserved, but she thinks that our techniques aren鈥檛 yet sensitive enough to reliably detect them.
