Experts Tested DNA From A Teenage Girl And Uncovered A New Type Of Human

The cave in question was in the Leang Panninge archaeological site, situated on the isle of Sulawesi. This is the largest island in the Wallacea group, which also includes Timor, Flores, and Lombok. For biologists and researchers concerned with the study of evolution, this region really is unlike any other.

Wallacea takes its name from the scientist Alfred Russel Wallace, who spent years exploring the region during the 19th century. Inspired by the unusual creatures he encountered there, Wallace formulated a theory of natural selection. It’s fair to say, then, these remarkable islands helped him to unlock many secrets about how nature really works.

During his trip to Wallacea, Wallace discovered thousands of previously unknown animal species. The region showed him a whole new side of the natural world, but even he couldn’t have realized the extent of the secrets hidden away there. Who knows what he might have made of the skeleton excavated from the Sulawesi cave in 2015?

This skeleton had belonged to a teenage girl, aged around 17 or 18 when she died. Amazingly, it seems that she’d lived well over 7,000 years ago. The discovery could be considered special for that reason alone, but there was more to it than that. This ancient lady was different. The experts had never seen anyone like her.

It’s unfortunate that Wallace never had the chance to see this skeleton, as his reflections would surely have been interesting. Nonetheless, he left us with enough to ponder after his own trip to the region that would one day bear his name. His journey began in 1854 with a voyage through the Malay Archipelago, which today includes the island nations of Indonesia and Malaysia.

As he traveled from island to island, Wallace realized something bizarre. The animals in one section of the archipelago were markedly different than the creatures in the other part. On the one hand, islands on one side tended to host marsupials and strange species of monkey. Whereas in the other territory, which wasn’t far away at all, larger creatures such as rhinos, tigers, and elephants could be found.

Wallace imagined a boundary splitting up these two parts of the Malay Archipelago, which we today call Wallace’s Line. Even though islands on either side of the line are situated close to one another, they’re still really distinct. Animals that are well adapted to one side might find conditions on the other totally unsuitable.

The region that stretches from Wallace’s Line to New Guinea is today called Wallacea, with Sulawesi being the biggest island found there. The region hosts an abundance of strange and unique animals, which is probably why it interested a top naturalist such as Wallace so much. Even if we take birds alone, we know of 697 species throughout the region today. Of these, around a third can’t be found anywhere else in the world.

Roughly 200 types of mammal live throughout Wallacea, with more than half of those being totally unique to the region. Some amazing creatures are among those numbers, such as a small relative to the buffalo known as the anoa. There’s also a strange kind of pig called the babirusa, which is distinguishable by its upward-pointing tusks.

Several species of primate can be found in Wallacea, particularly on the large island of Sulawesi. Seven special kinds of macaque can be found here and nowhere else, not to mention a number of tarsiers. These are small, wide-eyed monkeys that almost look closer to amphibians with hair than they do a type of primate.

Wallacea is also home to a great array of reptiles, with up to 188 species recorded so far. Of all these, around 65 percent are unique to the region. One of these endemic species has even gained a certain degree of notoriety, as people all over the world have heard of the Komodo dragon. These can only be found naturally on a few of the region’s isles.

Hundreds of fish species have been noted in the waterways of Wallacea, though research is lacking in this area. Still, even given the relatively low levels of investigation into Wallacea’s fish, we know of around 210 species that live there. On Sulawesi specifically, there are 69, with most of these being unique to the island.

When it comes to plants in Wallacea, research has also been somewhat lacking. Compared to nearby places, the islands of Wallacea have been studied less than you might expect. Insects and other invertebrates also need to be investigated more rigorously if we’re to learn more about the region’s incredible ecosystem.

We might not know enough about the insects of Wallacea, but we’ve still identified some fascinating species. The birdwing butterfly, for one, has been studied extensively. And the region is also home to Chalocodoma pluto, which is the biggest bee on Earth. These things can reach about an inch and a half in length, which as bees go is unsettlingly large.

Given all the weird and marvelous creatures roaming around Wallacea and its surrounding areas, it’s no surprise that Alfred Russel Wallace was so enthused about it. And thankfully for the rest of us, he published an account of the things he saw there. The Malay Archipelago was full of rich details of what he encountered.

As well as enrapturing Wallace, the archipelago also inspired his scientific mind. During his stay there, he started to come up with ideas about how living things change over time. He consequently came up with a theory of natural selection, which he decided to share with another naturalist by the name of Charles Darwin.

Darwin had also been working out his own thoughts on natural selection at that time, though he hadn’t yet presented his ideas to the world. That would come later, with the publication of The Origin of Species. With that, it was Darwin who would come to be most associated with the theory of natural selection. Even so, it’s said that Wallace wasn’t jealous.

Wallacea and its surrounding islands helped Wallace to reach conclusions about the nature of evolution, but he really only scratched the surface. More discoveries were yet to come from the region — and some were directly related to the murky history of human beings. On Sulawesi, for instance, an incredible piece of cave art has proven to be particularly telling.

The art seems to show people hunting some animals, which doesn’t seem that groundbreaking on its own terms. But when you consider the work’s age, its significance is pretty plain to see. Experts think this was painted over 44,000 years ago, which is more than twice as old as cave paintings in Europe that were previously considered the oldest examples of narrative art.

The caves of Sulawesi are phenomenal places, potentially full of clues related to the long history of our own species. Indeed, it was in just such a place where the skeleton of that ancient teenage girl was found back in 2015. With that, experts had encountered something that challenges everything that we thought we knew about our ancestors.

The archaeologists who excavated this 7,200-year-old skeleton named her Bessé’, which we pronounce as bur-sek. This word comes from the Bugis ethnic group, who live in the southern end of Sulawesi today. These people use the term to denote a newly born princess in their culture. Clearly then, the researchers realized how important this skeleton was.

As they subjected Bessé’s remains to testing, the archaeologists managed to extract DNA from her. This was the first time that DNA this old had ever been recovered from Wallacea, which was impressive in and of itself. But when they examined it properly, they realized that our whole understanding of ancient humans was being turned on its head.

The DNA was taken from a section of Bessé’s skull known as the temporal bone. But really, it’s quite amazing that this was remotely possible. These remains were many thousands of years old, and they’d spent that time in a really warm part of the world. The fact that they hadn’t totally deteriorated is quite remarkable.

One of the researchers involved in this project was Professor Adam Brumm, from Griffith University in Australia. Speaking to U.K. newspaper The Guardian in 2021 about the improbability of extracting DNA from Bessé’, he said, “The humid tropics are very unforgiving on DNA preservation in ancient human bones and teeth… There’s only one or two pre-neolithic skeletons that have yielded ancient DNA in all of mainland southeast Asia.”

Unlikely as it was, though, DNA was recovered from Bessé’ — and it turns out that it’s really unusual. Roughly half her genes are similar to what we’d see in the indigenous populations of Australia, the western Pacific islands, and New Guinea today. That’s all well and good, but it’s the other parts of her DNA that were most interesting to researchers.

It seems that Bessé’ had genetic links to the east of Asia, which just isn’t what was expected. And while that might not sound like a groundbreaking discovery to the layperson, the experts were blown away by this news. After all, it throws a spanner into the works of their whole understanding of human migration.

Speaking to The Guardian, Brumm reflected, “It is thought that the first time people with predominantly Asian ancestry entered the Wallacean region was around about three or four thousand years ago, when the first prehistoric neolithic farmers entered the region from Taiwan… If we’re finding this Asian ancestry in a hunter-gatherer person who lived thousands of years before the arrival of these neolithic people from Taiwan, then it suggests… earlier movement of some population from Asia into this region.”

And that’s not all that the researchers figured out from looking at Bessé’s DNA. It turns out that she was a member of the Toalean culture, which makes her the first such person to ever be uncovered by archaeologists. Before now, evidence has pointed towards the Toaleans having existed, but nothing concrete had ever been established.

Archaeologists first became aware of the Toalean culture at the start of the 20th century, in 1902. That was when two scientists from Switzerland discovered stone arrowheads and tools in caves around the south of Sulawesi. They believed these things had been fashioned by ancient inhabitants of the island, whom we now call the Toaleans.

In an email to CNN in 2021, Professor Brumm summed up the story of the Toaleans. He wrote, “The ‘Toaleans’ is the name archaeologists have given to a rather enigmatic culture of prehistoric hunter-gatherers that lived in the forested plains and mountains of South Sulawesi between around 8,000 years ago until roughly the fifth century A.D.… They made highly distinctive stone tools (including tiny, finely crafted arrowheads known as ‘Maros points’) that are not found anywhere else on the island or in wider Indonesia.”

Brumm explained that the Toaleans had used to fashion tools out of stone, some of which had been really quite intricate. Perhaps the most notable of these is something called a “Maros point.” This is a special type of arrowhead that the Toaleans clearly took a great deal of care in forging.

The tools and implements of the Toaleans have tended to be found only in a specific area of Sulawesi. That implies that these people were pretty secluded from any other groups that also lived on the island or in the wider region. In other words, the Toaleans seem to have developed their culture in isolation.

Experts have long pondered the Toaleans, speculating about where they originally came from. Getting any detailed answers about their heritage, however, has proven difficult. That changed, of course, when Bessé’s DNA was studied. Finally, these researchers had actual DNA from one of the Toalean culture’s members to pore over.

The first humans to show up in the Wallacea region are thought to have done so around 65,000 years ago. Some experts previously speculated that the Toaleans were actually related to these early people — and it seems they were right. Thanks to Bessé’s DNA, experts now have evidence to back that claim up.

There’s a big question over how early humans actually managed to make it to the islands of Wallacea. One major idea, though, is that they sailed there. Even though they lived thousands of years ago, it seems they must have built and navigated fairly refined boats to get there.

Bessé’s DNA contained so many unexpected details that blew the experts away. Another one was that she appeared to be related to an entirely different species of human known as the Denisovans. Most evidence of this species has come from places such as Tibet and Siberia, so discovering a link to them somewhere as far away as Wallacea is a surprise.

Cosimo Posth is a professor for the University of Tübingen’s Senckenberg Centre for Human Evolution and Palaeoenvironment, which is based in the German city of Frankfurt. Posth was closely involved in the study of Bessé’, and he spoke about her links to the Denisovans in a 2021 statement. He said, “The geographic distribution of Denisovans and modern humans may have overlapped in the Wallacea region.”

As Posth sees it, the islands of Wallacea may once have been a very important place. It seems that they were a hub of activity for early humans of different species. As he put it, “It may well be the key place where Denisova people and the ancestors of indigenous Australians and Papuans interbred.”

Bessé’ has changed the way that experts think about human history, but more work obviously needs to be done. Professor Brumm put this point concisely in a 2021 statement of his own. He said, “The discovery of Bessé’ and the implications of her genetic ancestry show just how little we understand about the early human story in our region, and how much more there is left to uncover.”