The Turin Shroud bears DNA from many people, plants and animals

DNA analysis has identified a vast array of animal, plant and human material contaminating the Turin Shroud, complicating the story of the mysterious relic purported to be the cloth that Jesus Christ was wrapped in after his crucifixion 2000 years ago.

The shroud, which measures 4.4 metres long and 1.1 metres wide, is one of the world’s most famous and controversial Christian artefacts. Its first documented location was in France in 1354, and for nearly half a millennium, it has remained at the Cathedral of Saint John the Baptist in Turin, Italy.

In 1988, researchers used radiocarbon and accelerator mass spectrometry dating techniques to determine that the shroud was made sometime between 1260 and 1390, excluding the possibility that the person perceived as being imprinted on the cloth could have been Jesus. However, this dating of the shroud to the later medieval period remains contested by some scholars of Christianity.

In 2015, Gianni Barcaccia at the University of Padova, Italy, and his colleagues analysed material collected from the relic in 1978 and first suggested that the cloth may have originated in India.

Now, Barcaccia, who declined to be interviewed for this story, has led a new study reanalysing the 1978 material. He and his team found that the shroud has preserved a huge diversity of medieval and modern DNA.

The sources of genetic material include domestic cats and dogs, farm animals including chickens, cattle, goats, sheep, pigs and horses, and wild animals such as deer and rabbits.

The team also found traces of some fish species, including the grey mullet, Atlantic cod and ray-finned fishes. Marine crustaceans, flies, aphids, and arachnids like dust and skin mites and ticks were also identified.

Some of the most common plant species whose DNA was preserved on the shroud are carrots and various wheat species, as well as peppers, tomatoes, and potatoes – plants probably brought to Europe after explorers began travelling to Asia and the Americas.

However, it wasn’t possible to determine the exact timing of these plant and animal contamination events.

The team also found human DNA from many individuals who have handled the shroud, including the 1978 sampling team. “The Shroud came into contact with multiple individuals, thereby challenging the possibility of identifying the original DNA of the Shroud,” they write.

Nearly 40 per cent of the human DNA found on the shroud is from Indian lineages, which “could have resulted from historical interactions or the Romans importing linen from regions near the Indus Valley”, Barcaccia and his colleagues report.

“The DNA traces found on the Shroud of Turin suggests the potentially extensive exposure of the cloth in the Mediterranean region and the possibility that the yarn was produced in India,” the team writes.

Anders Götherström at Stockholm University in Sweden says the earlier research dating the shroud to the 13th century is generally accepted in the scientific community. “While there is some debate around the 1988 radiocarbon dating, most researchers consider it sufficiently robust,” he says.

Götherström is unconvinced by the suggestion that the cloth may originate from India. “I still see no reason to doubt that the shroud is French and from the 13th-14th century,” he says.

“The shroud has a history of its own as an important relic, and that history may be more interesting than a legendary origin… without scientific support.”