It was the first stop on an extraordinary journey. On a bright but bitterly cold January afternoon earlier this year, I found myself on a small island in the Black Sea, just off Sozopol on the east coast of Bulgaria. Sveti Ivan has long been a destination for travellers: it boasted a temple of Apollo in ancient times. But I was there to speak to an old Bulgarian archaeologist about the most important find of his career.
In 2010, Kasimir Popkonstantinov discovered what he believes are the bones of one of the most famous of all saints: John the Baptist. I was interested in what DNA analysis could tell us about these bones, and other ones. Together with biblical scholar Joe Basile, I was travelling around the world filming a documentary about the religious and scientific evidence linking archaeological artefacts to Jesus Christ himself.
Popkonstantinov made his discovery when excavating a sixth century church on the island, built on top of a basilica from the century before. As he carefully scraped through the mud where the altar would have been, he came across a stone slab and was amazed to find a small marble box underneath. He immediately knew what it was. For a church to be consecrated in this part of Europe in the fifth century, it needed to contain a relic from a holy saint or religious person. This box, known as a reliquary, would have housed such a relic.
He continued to dig around and found another, smaller box about a metre away. On the edge of the inferior box was an inscription: “May God save you, servant Thomas. To Saint John.” When Kasimir later opened the reliquary, he found five bone fragments. The epitaph on the smaller box, probably used to carry the bones when travelling, was the key piece of evidence that led him to believe that the bones could perhaps be those of John the Baptist. The finding is hugely important, partly because John the Baptist was both a disciple of Jesus and his cousin – meaning they would share DNA.
Thanks to a number of scientific advances, the field of ancient DNA – the extraction and analysis of genetic material from bones and fossils of organisms dug up out of the ground – is booming. We now have DNA sequences from hundreds of people who are long since dead, and analysis of these sequences is further refining our understanding of human history.
DNA as proof of identity
I was initially sceptical about what the Bulgarian bones could teach us. For a start, no DNA test can prove that these were bits of John the Baptist, Jesus or any other specific person. We can’t extract and analyse an unknown DNA sample and magically say that it belonged to this or that historical character. To do that, we’d need to have a DNA sample that unambiguously came from John the Baptist that we could compare the bones to. So sequencing DNA in itself is not going to be too helpful.
Another major consideration is the risk of contamination. In an ideal scenario, ancient material we want to use for genetic analysis should be untouched by anyone since that person had died. The best ancient samples are dug out of the ground, put into a bag, and then sent straight to an ancient DNA lab. In the 500 years between John’s death and the bones being sealed in the church, any number of people could have handled them and left their DNA behind.