DNA reveals details of those on ship that sank in 1628
On the afternoon of Aug. 10, 1628, the Vasa, built by the Swedish to be one of the most powerful warships in the Baltic, set off from the palace docks in Stockholm.
The Vasa did not even make it 1 mile.
A strong gust of wind caused the 226-foot-long ship to keel over as water poured in through its open gun ports, which were on display for its maiden voyage.
About 150 people were believed to be on board when it sank; about 30 died.
Now, nearly 400 years later, advanced DNA testing is allowing researchers to learn more about the ship’s dead, including a woman known as “G,” whom researchers had long believed to be a man.
“It’s fascinating to get a sense of who they are as individuals, but also what they tell us about what the Swedish population was like 400 years ago,” said Fred Hocker, the director of the Vasa Museum in Stockholm, where the ship is displayed.
The Vasa’s resurrection began in 1958 and was completed in 1961 when the entire warship was lifted from the depths of Stockholm harbor.
Workers sprayed the ship with water, then applied the preserving agent polyethylene glycol over the course of 17 years and let it dry for another nine years. The mud from the seafloor, it turned out, had kept the ship in remarkable condition.
A handful of similar excavation projects of historic ships were underway around the same time, Hocker said. But the Vasa, he said, “is the most spectacular.”
“It’s a whole ship! It’s huge!” he said. “The Vasa established the mold for what maritime archeology could be.”
The recovery included more than 40,000 objects in and around the ship. However, the skeletal remains found inside the boat “posed something of an archeological problem for us,” Hocker said.
The remains were initially given a Christian burial in a naval cemetery. Twenty-six years later, as the Vasa Museum was preparing to put the ship on display, the bones were exhumed for further study.
They were not in ideal condition.
Still, in 2004, the museum began working with genetics experts at Uppsala University in Sweden to do a baseline DNA study of the remains using mitochondrial DNA testing, which helps to link skeletons via maternal relationships but does not reveal granular details, such as sex.
Researchers concluded that there were 15 “well-defined” adults and some bones that accounted for at least two other people, including a child younger than 10.
That’s when Marie Allen, a professor of forensic genetics at Uppsala University, turned to Kimberly Andreaggi, a former student who was working at the US Armed Forces DNA Identification Laboratory.
“They had developed a panel that is very informative. It’s already developed, and they tried it on difficult samples,” Allen said. “That’s the beauty of research; many times, it’s much easier to collaborate and help each other in different projects than to reinvent the wheel all the time.”
In 2016, the lab developed a “next-generation sequencing method” that could capture and enrich DNA that had been damaged or compromised, said Charla Marshall, chief of the lab’s emerging technologies section.
The first Vasa sample researchers tested was from G. Her name derived from a system in which researchers assigned a letter to remains corresponding to the order in which they were recovered.
While G’s sample was damaged, it was better preserved than remains the lab normally examines, Marshall said. After fully sequencing G’s DNA using four different methods, the lab was able to determine her sex.
Researchers struggled to get G’s full genetic makeup, in part because her bone structure was androgynous: Her facial bones looked “a little bit more male than female,” Hocker said, and her spine appeared to have “lived a life of very hard work.”
So why was G on the Vasa? Researchers can’t say for certain, but they do have theories.
The Swedish Navy allowed sailors’ wives to live on warships while in home waters. G was found next to a male skeleton, as were two other female skeletons.
“In the tragic moment of sinking, it’s not hard to imagine that husbands and wives found each other,” Hocker said.
There is also a chance, however highly unlikely, that G passed as a man on the ship, Hocker said.
“We only know about the cases where people were discovered,” he said of women who passed as men on warships. “We don’t know about any of the people who pulled it off and were never discovered.”