Shroud of Turin, claimed to be Jesus' burial cloth, contaminated with carrot and red coral DNA

The Shroud of Turin, which some people claim is Jesus' burial cloth, contains the DNA of multiple people, along with a huge array of other species, including carrots, melons and red coral.

Some of the DNA traces suggest there's an influence from India, which could mean the cloth originated there, researchers argue in a new study.

However, there was a notable absence of species traditionally associated with the Levant region and stories in the Bible. What's more, some of the plant species detected on the shroud did not arrive in the Old World until the 16th century, which suggests the shroud was contaminated centuries later, experts told Live Science.

Overall, the scientific evidence still firmly supports arguments that the Shroud of Turin is a medieval fake, they said.

Likely a fake

The famous shroud has moved around Europe for centuries, but the first documented mention of the shroud was in Lirey, a village in northern France in 1354, and even then, there were debates about whether it was an authentic relic from the crucifixion. The rectangular cloth measures 14.4 by 3.6 feet (4.4 by 1.1 meters) and bears the faint image of a man and numerous stains, some of which are claimed to be blood.

The most robust evidence for the shroud's age comes from a carbon-dating analysis carried out in 1989, which placed the shroud's creation between 1260 and 1390, firmly in the medieval period. And last year, work revealed that the human image on the shroud probably resulted from the cloth being laid on a low-relief sculpture.

Some Christian scholars still believe the shroud is genuine and dates back 2,000 years. Yet there is no evidence that the multishaft looms required to manufacture the type of cloth in the shroud existed in Europe, India or the Levant region 2,000 years ago.

"These structures need a loom with four shafts that was invented in the Middle Ages [in Europe]," Andrea Nicolotti, a historian at the University of Turin who wasn't involved in the work, told Live Science.

Analyzing the DNA

In 2015, Gianni Barcaccia, a professor of genetics and genomics at the University of Padova in Italy, and his colleagues suggested that the Shroud of Turin may have been made in India, based on a genetic analysis of samples collected from the shroud in 1978.

More powerful genomics techniques are available now, so Barcaccia and his colleagues did a new DNA and metagenomic analysis on the samples from 1978 to determine which species any traces of DNA came from. The research was posted to the preprint server bioRxiv March 22 and has not been peer-reviewed yet.

The researchers found human DNA that seems to have come from multiple people, one of whom was the person who collected the samples in 1978. Bacterial species accounted for 10% to 31% of the DNA. Barcaccia's team noted the presence of DNA from Mediterranean red coral (Corallium rubrum), which suggests "Mediterranean origins or transit through Mediterranean regions."

Even if the coral came from a particular place, however, it doesn't mean the shroud was there, too, Nicolotti noted. "Red coral perhaps makes people think of the sea of Palestine," he said, adding that there was a much more likely scenario for how coral ended up on the shroud. "It makes me think of the coral crucifixes and rosaries, or reliquaries that we know were placed in contact with the cloth."

Barcaccia's team found that cats and dogs accounted for about 44% of the animal DNA, but there were also traces from chickens, cattle, goats, sheep, pigs, horses, deer and rabbits. In addition, there were slight traces of skin mites, ticks and an assortment of fish.

Plants species were richly represented too. Carrot DNA provided about 31% of the plant DNA. But there was also DNA from wheat, maize, rye, peppers, tomatoes, potatoes, melons or cucumbers, and peanuts, as well as traces of grasses, bananas, almonds, walnuts and oranges.

Some of these plants may reflect typical agricultural practices in Europe and the Mediterranean, the study authors wrote, but some of those plants, such as bananas, potatoes, peppers and tomatoes, were introduced to Europe mainly from the Americas in the 16th century and later. And the carrot DNA is genetically similar to cultivars bred from orange carrots originally grown in Western Europe between the 15th and 16th centuries, which suggests relatively recent contamination, Barcaccia told Live Science via email.

"We are confident that this diversity of animal and plant species identified highlights the significant environmental contamination of the shroud that likely occurred in recent centuries, particularly following the voyages of Marco Polo and Christopher Columbus," he said.

Notably, some species historically associated with the Mediterranean region were lacking.

"The vast range of animal and plant material doesn't seem indicative of any particular environment, but I note the absence of olives, dates, pomegranates, camels and of course myrrh and aloes," Hugh Farey, an independent researcher who runs a blog called The Medieval Shroud and wasn't involved in the work, told Live Science via email.

Human DNA can be transferred to an object with or without touch, and it’s the same with DNA from other animals and plants, so many traces may have ended up on the shroud due to its public displays in medieval cities. "All the vegetables make me think of the market that is 100 meters [330 feet] from the square where public exhibitions were held for centuries in Turin, or of the dust of Chambéry when the Shroud used to be displayed along a tree-lined avenue," Nicolotti said.

The researchers dated a couple of threads in the shroud, one to between 1451 and 1622 and the other to between 1642 and 1800. These dates align with when the shroud was repaired in 1534, not long after it was damaged by fire, and in further conservation work in 1694, the team noted.

Importantly, none of the new findings contradict the definitive carbon-dating analysis carried out in 1989, Nicolotti said.

However, what's more controversial is Barcaccia and colleagues' interpretation that nearly 40% of the human DNA found on the shroud is from Indian lineages, suggesting "the possibility that the yarn was produced in India."

Nicolotti doesn't think the shroud is likely to have come from India and remains convinced it is a forgery originating in medieval Europe as the carbon dating from 1989 implies. He is also not surprised that a range of human DNA was found on the cloth.

"I try to imagine how many people must have touched the shroud, all the instruments used by the American scholars in 1978, and even who may have touched and made the brushes that were used to dust the shroud periodically," he said.