DNA recovered from the Shroud of Turin largely reflected modern handling and environmental exposure, limiting its ability to establish the artifact’s age or origin, according to a study published in Scientific Reports.
Scientists at the University of Padova in Italy, examined 12 specimens from an official sample collection obtained in 1978. The specimens included linen fibers, dust, and a small biological fragment.
The researchers extracted DNA under clean-room conditions using a method designed for highly fragmented genetic material. They then applied shotgun next-generation sequencing, mitochondrial DNA analysis, metagenomic profiling, and bioinformatics to identify human, microbial, plant, and animal DNA. Seven samples produced enough DNA for sequencing.
Although the samples contained short DNA fragments, more than 98 percent lacked the molecular damage patterns generally associated with ancient DNA. Contamination testing also identified clear evidence of modern DNA.
The predominant mitochondrial lineage matched the mitochondrial genome of Pierluigi Baima Bollone, who collected the samples in 1978. Genome-wide analysis indicated that DNA from three samples came from either Baima Bollone or a first-degree relative. Other mitochondrial variants associated with Western Eurasian and Near Eastern populations were also detected, but the mixture of genetic material prevented the researchers from linking the DNA to an original individual.
The samples also contained bacteria commonly found on human skin, including Cutibacterium and Staphylococcus, supporting repeated direct handling. Salt-tolerant microorganisms, yeasts, molds, and skin-associated fungi were identified as well.
Plant and animal DNA came from a wide range of sources, including cultivated crops, livestock, domestic animals, and Mediterranean red coral. Genetic material from crops introduced to Europe during or after the Middle Ages suggested that at least some contamination occurred relatively recently.
Proteomic testing detected skin-associated proteins but found no evidence of ancient peptides. This further supported the conclusion that much of the biological material resulted from handling.
The researchers also radiocarbon dated two linen threads recovered from the Shroud’s casket. Their estimated dates aligned with documented repairs in 1534 and 1694, but the threads were not used to determine the age of the Shroud itself.
The study illustrates how sample history, handling, environmental exposure, and modern contamination can complicate molecular analysis. Even when sensitive sequencing methods recover DNA from historical material, the results may not identify when that material was deposited or who deposited it. The researchers concluded that metagenomic testing could not determine whether the Shroud was medieval or approximately 2,000 years old.
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