DNA from the deep? Antikythera shipwreck yields ancient human bones

14

Site has already revealed most spectacular cargo ever found from antiquity, but bones are first hope of sequencing DNA from 1st century BC shipwreck victim

Death, when it came, was sudden and cruel. The individual, either a crew member or passenger, was trapped on board when the huge ship foundered. Dashed on the rocks, the vessel slid beneath the waves, tumbled down an undersea cliff, and swiftly became buried in sediment on the seabed.

Now, more than 2,000 years later, archaeologists have recovered the bones of the individual they now call Pamphilos. Thought to be a man in his late teens to early 20s, he was on the ship sailing from Asia Minor to Rome when disaster struck off the tiny Greek island of Antikythera between Crete and the Peloponnese.

The catastrophe in the first century BC scattered the ships cargo across the seabed. It lay there until 1900, when sponge divers found it by chance in 50 metres of water. Salvage operations have since hauled up stunning bronze and marble statues, ornate glass and pottery, gold jewellery, and an extraordinary geared device the Antikythera mechanism which modelled the heavens. The cargo, for good reason, is considered the most spectacular ever found from antiquity.

With the latest discovery of human bones, scientists have their first real hope of sequencing DNA from a victim of an ancient shipwreck. The only comparable efforts have focused on remains from King Henry VIIIs great ship, the Mary Rose, and the Swedish warship Vasa, which sank on her maiden voyage in 1628. If the ancient bones contain intact DNA, it will cast fresh light on the ill-fated ships occupants.

This is the most exciting scientific discovery weve made here, said Brendan Foley at Woods Hole Oceanographic Institution, who is exploring the wreck site with archaeologists from the Greek Ephorate of Underwater Antiquities. We think he was trapped in the ship when it went down and he must have been buried very rapidly or the bones would have gone by now.

Theotokis
Theotokis Theodoulou and Brendan Foley examine some of the bones, which are discoloured a dark reddish-brown, possibly through age, or perhaps from the uptake of iron leached from nearby artefacts. Photograph: Brett Seymour/EUA/WHOI/ARGO

Foley was diving on the site at the end of August when one of the team swam over and tapped him on the shoulder. Talking through his rebreather in muffled excitement, Nikolas Giannoulakis said: We found bones! We found a skeleton! The diver held up what later turned out to be a forearm bone. On reaching the trench the team was excavating, Foley saw long bones poking from the silt. There was no doubt in any of our minds that what were were looking at were extensive human remains.

3D photogrammetry of the human bones found at the Antikythera shipwreck site. Credit: Brett Seymour/EUA/WHOI/ARGO

The skeleton was found in a jumble. Arm bones overlay leg bones. The skull, teeth, and pieces of rib were nearby. Broken ceramics and other fragmented artefacts lay all around. More bones are still encased in the sediment, but to excavate those is to risk an underwater landslide.

Foley calls the skeleton Pamphilos because the common Greek name, meaning friend of all, had been scratched into a cup decorated with an erotic scene found nearby on a previous salvage expedition. The cup demonstrates that at least one person on the ship was literate, not to say worried that someone might steal his drink. We dont know if he was the owner of that cup, but there was a a Greek male on board by that name, Foley said.

The ancient bones are a dark reddish-brown, the discolouration brought on by age, or perhaps from the uptake of iron leached from nearby artefacts. Some of the bones were like wet chalk and fell apart on handling. But many others, including the leg bones, survived intact. Details of the discovery were first reported by Nature.

The
The team examining the bone find. The bones probably survived because the ship sank fast into the cool depths and was buried by a mound of silt that slid down the cliff after the vessel. Photograph: Brett Seymour/EUA/WHOI/ARGO

There is little wear on the teeth and the bones in the skull are not fully fused, pointing to an upper age of about 25 years. Meanwhile, the upper leg bone is thicker than might be found on a female. The bones probably survived because the ship sank fast into the cool depths and was buried by a mound of silt that slid down the cliff after the vessel.

Foley expected to find human remains on the wreck and had one of the worlds leading experts in ancient DNA, Hannes Schroeder at the Natural History Museum of Denmark, lined up to help. While the bones are not the first to be found on the wreck Jacques Cousteau surfaced with a pile of fragments from the site in 1976 these are far more complete and apparently better preserved.

The
The bones in the skull are not fully fused. That, plus little wear on the teeth points to an upper age of about 25 years. Photograph: Brett Seymour/EUA/WHOI/ARGO

In the past, archaeologists have not been equipped to make the most of human remains. But science has changed in the past decade. Human remains have started to become a source of information that can tell us incredible things about the past, Schroeder told the Guardian. Even with a single individual, it gives us a potentially great insight into the crew. Where did they come from? Who were these people?

In a stroke of good luck, the remains include the petrous bone, the hard part of the skull behind the ear. Dense and impenetrable to water and microbes, this is Schroeders best hope for finding intact DNA. With permission from the Greek authorities, he can attempt to extract the genetic material. Given the green light, he could read its secrets before the end of the year.

Confirming the sex of the individual should be straightforward. More interesting will be the persons ancestry. Armed with a full DNA sequence, Schroeder can use geographical maps of genetic variation to see where Pamphilos may have come from: the Levant, the Greek mainland, North Africa, or the Black Sea region.

3D photogrammetry of a human bone recovered from the Antikythera shipwreck site in 2016. Credit: Brett Seymour/EUA/WHOI/ARGO

His appearance and more than simply his hair, eye and skin colour will also be written into the DNA. Mark Shriver, an anthropologist at Penn State University, is working on how to infer facial features from DNA. At least some details of the persons appearance might be gleaned from the DNA if the bones are well preserved.

If it was under enough silt, there is the potential. The ancient DNA results around today are impressive compared to what we saw even five years ago, he said. Just by getting sex and ancestry you can get about one quarter of the total facial variation. Age too, is another big factor.

Argyro Nafplioti, an osteoarchaeologist at Cambridge University, has studied pieces of human bones brought up from the shipwreck in 1900 and 1976. The fragments are poorly preserved and incomplete, but appear to come from at least four adults, one of whom was probably female.

Brendan
Brendan Foley compares amphora styles on the Antikythera shipwreck. Photograph: Brett Seymour/EUA/WHOI/ARGO

She said the recovery of more human skeletal remains was very important and could potentially add to scientists understanding of who was on board the ship. Through further bioarchaeological research we can now aim to get a better idea of the number of people on board, their biological sex and age at death. On top of that, further evidence can shed more light on the quality of life conditions and the physical activities of the crew, she said.

My study presented evidence for female presence on board. This is not surprising, as passenger ships did not exist at the time, and cargo vessels like this one accommodated passengers and their servants. In the light of the new findings it will be interesting to see if in fact more than one female were present, as passengers or servants to passengers, she added.

Whoever the latest remains belong to, they are more than a pile of ancient bones, Schroeder said. It was a particularly cruel way for this person to go and you do think about that. If they are forgotten, maybe thats not so nice either, and one way of honouring these individuals is to tell their stories, he said.

How much of a story the scientists can tell is not yet clear. This is uncharted waters. Ive never dealt with submerged remains like this before, Schroeder said. We wont know if it works until we try, but it is definitely worth trying.

Read more: https://www.theguardian.com/science/2016/sep/19/antikythera-shipwreck-yields-human-bones-bringing-hope-for-dna-secrets-from-the-deep