Almost five millennia ago, the remains of an ancient Egyptian man were placed in a ceramic pot and entombed in a hillside.
While his identity is still a mystery, scientists have extracted and sequenced his genetic data.
The genome, described in a study published in Nature, is the oldest DNA extracted from an Egyptian human to date, and the first entire genome sequenced from an ancient Egyptian.
The man, whose skeleton was unearthed from a necropolis at Nuwayrat, 265 kilometres south of Cairo, lived between 2855 – 2570 BC.
His DNA potentially helps us understand the members of the culture that built the pyramids, according to Adeline Morez Jacobs, first author on the paper and a research fellow at Liverpool John Moores University.
"The question of 'who the ancient Egyptians were' is something people are really curious about," Dr Morez Jacobs said.
"There are all kinds of theories out there," she said.
So, what can we learn from a set of ancient bones buried in a plain clay pot while, or even before, the Sphinx was being constructed?
Ancestry of the skeleton in the pot
The Nuwayrat pot was excavated between 1902 and 1904 by a United Kingdom-led team, while Egypt was under British rule.
Previous analysis of the skeleton in the pot suggested it belonged to a man aged between 44 – 64 years old at time of death.
The man was also believed to be of higher-status, based on how burials were usually done at this time.
To find out more about him, the team carbon dated the skeleton, which suggested he lived just before or during the Old Kingdom period when the oldest, and many of the most famous, pyramids were built.
Then they took seven tiny samples of the man's teeth for DNA extraction, and found two of them well-preserved enough to collect an entire genome.
The team then compared the man's genome against a database of 4,000 other people's DNA — 3,233 people from the present day, and 805 ancient people.
This comparison suggested the man's ancestry was mostly North African, but about a fifth of it also matched genes from ancient Mesopotamia, in modern-day Iraq.
They also analysed chemical signatures in his teeth that suggested he grew up in the Nile.
Dr Morez Jacobs said the team wasn't surprised by the results.
"His genetic ancestry largely aligns with neighbouring populations of the time."
This could add to the evidence that there was human migration between these two regions.
Bastien Llamas, an ancient-DNA researcher at the University of Adelaide, said the researchers had performed a solid, careful analysis.
"It's quite interesting to see that there is already, potentially, movement across the region that leads to this kind of mixture," Dr Llamas, who wasn't involved with the study, said.
But, he added, the researchers' analysis was very resource-intensive, and they could have reached the same conclusions by focusing on key parts of the man's genome and examining just a thousanth of the 8 billion data points they looked at.
"Targeting 1.2 million of those letters is much, much cheaper."
Why has it taken so long to do this?
While the dry Egyptian desert has been helpful for preserving pyramid superstructures over millennia, it's less friendly to tiny shreds of DNA.
Ancient DNA research is plagued by the problem that DNA is, usually, not a robust molecule.
It breaks down swiftly after death, and is even more likely to degrade in hot environments.
"Although advances in laboratory techniques have greatly improved our ability to recover ancient DNA, there's still significant uncertainty when working with material from hot and arid environments like Egypt," Dr Morez Jacobs said.
Some mummification and preservation techniques can also destroy DNA.
But Sally Wasef, a palaeogeneticist at Queensland University of Technology, said there was still plenty of well-preserved DNA found in ancient Egyptian tombs.
Dr Wasef, who wasn't involved with the current research, worked on DNA extraction from King Tutankhamun's family more than 15 years ago.
While they couldn't garner whole genomes, she said that ancient DNA extraction was now more powerful.
"I'm sure that we would be able to get more using the current techniques."
There can also be legal and logistical challenges when working with ancient DNA.
Dr Wasef said the Egyptian government has placed tight regulations on DNA sequencing, making it difficult to carry out the work with samples held in the country.
Artefacts moved overseas, however, can have patchy provenance, making it harder to link DNA with archaeological and historical information.
How much can the DNA of one person tell us?
While Dr Wasef said the researchers' DNA extraction was sound, she thought they might have drawn too many conclusions from their ancestry analysis.
"It's just one individual that has been moved outside of Egypt."
Dr Wasef said one individual's genes couldn't yield much information about migration, and the century-old excavation history lacked details that could possibly tell us more about the man.
She also pointed out that it's harder to determine ancestry from this region, because there's less genetic data from both ancient and modern people in the area.
"The ancient DNA results are as good as the database that you're comparing to."
Egyptian researchers are currently working on building a library of modern and ancient Egyptian DNA, due to be complete in the next couple of years.
"I'll be more inclined to see those results when that data is published and this analysis is redone," Dr Wasef said.
