The Medieval DNA Biome

The recent survey of the DNA found amongst the hooverings from the back of the Shroud has been re-published in Scientific Reports, so now seems a good time to revisit it, with some contemporary references. In an email to the principal author Gianni Barcaccia, I wondered if he had compared his findings to any other, similar survey of the DNA of an historical artefact, and what such a comparison might reveal. He has not as yet responded, so I did a little investigation of my own. In January 2026, two months before Barcaccia et al. published their researches in the same online repository, Harinder Singh et al. deposited ‘Biological Signatures of History: Examination of Composite Biomes and
Y-Chromosome Analysis from da Vinci-associated Cultural Artefacts.’ The team took swabs from a chalk drawing by Leonardo da Vinci, and some letters by an elderly cousin, as well as three sketches by other people for comparison, and analysed the DNA they extracted from it.

The results are instructive. Although neither the methods nor the results are directly comparable with those from the Shroud, Singh et al. did publish a number of ‘Top Ten’ lists, of Bacteria, Eukaryotes and Viruses for the five artefacts (Figure S1, in the Supplementary Material). Let’s look at the eukaryotes – animals, plants, fungi and protozoa.

A). Chalk drawing, by Leonardo, the ‘Holy Child,’ from about 1470.
1). Tanacetum cinerariifolium – PLANT – A common sort of daisy.
2). Artemisia annua – PLANT – Wormwood, common and widespread.
3). Malassezia restricta – FUNGUS – common human parasite, associated with dandruff and dermatitis.
4). Canis lupus – ANIMAL – Dog.
5). Malassezia globosa – FUNGUS – common human parasite, associated with dandruff and dermatitis.
6). Citrus sinensis – PLANT – Orange, common and widespread.
7). Acer saccharum – PLANT – Sugar Maple, from North America.
8). Friedmanniomyces endolithicus – FUNGUS – From Antarctica?
9). Cannabis sativa – PLANT – Cannabis.
10). Malassezia arunalokei – FUNGUS – another skin yeast fungus.

B). The Letters, from an elderly cousin of Leonardo’s, dated around 1400, well before Columbus ‘discovered’ America.
1). Plasmodium ovale – PROTOZOA – associated with malaria
2). Lupinus albus – PLANT – White Lupin, originally from the Balkans, but common in Europe
3). Homo sapiens – ANIMAL – Man. No surprises there.
4). Stereum hirsutum – FUNGUS – Turkey tail, common and widespread.
5). Callithrix jacchus – ANIMAL – The Common Marmoset, from South America. That’s a surprise.
6). Malassezia restricta – FUNGUS – common human parasite, associated with dandruff and dermatitis
7). Hanseniaspora uvarum – FUNGUS – a yeast mostly associated with wine-making
8). Clonorchis sinensis – ANIMAL – Chinese liver fluke, almost entirely from China. Found in fish.
9). Rhinolophus ferrumequinum – ANIMAL – Horseshoe bat, common and widespread.
10). Saguinus oedipus – ANIMAL – The Cotton-top Tamarin, a rare South American monkey.

C). Pen and Ink Drawing, by Filippino Lippi, St John, about 1500.
1). Zea mays – PLANT – Maize. American, but imported from around 1500.
2). Cryptomeria japonica – PLANT – Japanese cedar. Found only in Japan.
3). Panicum miliaceum – PLANT – Millet, common and widespread.
4). Canis lupus – ANIMAL – Dog.
5). Malassezia restricta – FUNGUS – common human parasite, associated with dandruff and dermatitis.
6). Triticum aestivum – PLANT – Wheat, common and widespread.
7). Hordeum vulgare – PLANT – Barley, common and widespread.
8). Trichinella patagoniensis – ANIMAL – A South American nematode.
9). Malassezia globosa – FUNGUS – common human parasite, associated with dandruff and dermatitis.
10). Seteria viridis – PLANT – Foxtail, common and widespread.

D). Chalk drawing, by Andrea Sacchi, Man Caught in the Wind, 1625.
1). Taxus chinensis – PLANT – Chinese Yew, common and widespread.
2). Cryptomeria japonica – PLANT – Japanese cedar. Found only in Japan.
3). Malassezia restricta – FUNGUS – common human parasite, associated with dandruff and dermatitis.
4). Sus scrofa – ANIMAL – Pig.
5). Triticum aestivum – PLANT – Wheat, common and widespread.
6). Canis lupus – ANIMAL – Dog.
7). Hordeum vulgare – PLANT – Barley, common and widespread.
8). Alternaria alternata – FUNGUS- A leaf spot fungus, common and widespread..
9). Cichorium endiva – PLANT – Endive, common and widespread.
10). Trichinella patagoniensis – ANIMAL – A South American nematode.

E). Chalk drawing, by Charles Flipart, Man Sitting at a Dest, about 1740.
1). Taxus chinensis – PLANT – Chinese Yew, common and widespread.
2). Zea mays – PLANT – Maize. American, but imported from around 1500.
3). Lolium multiflorum – PLANT – Italian rye-grass, common and widespread.
4). Canis lupus – ANIMAL – Dog.
5). Olea europaea – PLANT – Olive, common and widespread.
6). Vermiconidia calcicola – FUNGUS – Grows on Italian rocks.
7). Malassezia restricta – FUNGUS – common human parasite, associated with dandruff and dermatitis.
8). Cryptomeria japonica – PLANT – Japanese cedar. Found only in Japan.
9). Sus scrofa – ANIMAL – Pig.
10). Salix suchowensis – ANIMAL – A Chinese willow.

The last three artworks are about a century apart, from c.1500 to 1700, and from different parts of Europe, but the list of thirty species in their three ‘top tens’ only contains 18 different names, and only 9 of them are unique. All three artworks contained Malassezia restricta, a very common human infection, and Canis lupus, the dog, which the authors rather bizarrely associate with wolf-hair paint brushes (there’s no such thing), but they all also contained Cryptomeria japonica, the Japanese cedar, which is confusing, and may relate more to where they have been stored recently than their historical associations. Six other species are shared by two of the three artworks, including pig, dog, wheat, barley and maize, none of which are very surprising – although maize was not a European crop, historically – but also a South American nematode, almost unknown outside Argentina. All the artworks are from the Fred R Kline collection, in New Mexico, which may be significant.

However, the da Vinci letters and the ‘Holy Child’ drawing do not share any of their ‘top ten’ DNA with each other or the three other artworks, apart from dog, in the Holy Child, and the ubiquitous Malassezia sp. They do, however, have idiosyncrasies of their own, including two kinds of Amazonian monkey, a Canadian maple, a Japanese cedar, and a rock fungus mostly associated with Antartica.

Note that although these are from ‘top ten’ lists, that does not necessarily mean any of them are abundant. In another table (Figure 2E, from the main paper), listing the top fifteen species of all kinds in each artefact, Plasmodium ovale is the only eukaryote to make it into the ‘Letter’ list. The monkeys may be among the top ten eukaryotes, but they don’t make it into the top fifteen species overall.

In another table still (Figure S2, Supplementary Material), the eukaryotes for each artwork are divided into ‘top tens’ of plants, fungi, animals and protozoa. Although only one animal (dog) made into the Holy Child’s top ten eukaryote list, others in tiny proportions included (from greatest to least percent of total biome), the Chinese racoon dog, the South American nematode mentioned above, the chicken, a marine worm, a Hawaiian fruit fly, a North American trout, man, and, smallest of all, a European fruitfly and the pig. Why there should be more DNA from a Hawaiian rather than a European fruitfly is a mystery.

The 50 animals listed as the top ten on each artwork (5 x 10) comprise only 30 different species because of overlap, and of those 30, 16 are found among the animals also identified on the Shroud – including the Giant Panda, the Common (South American) Marmoset, Chinese Raccoon Dog and the sub-Saharan Warthog.

Similarly, there are 34 different species of plant distributed among the five ‘top tens,’ of which only half a dozen or so are not among the Shroud list, but which, including the Shroud list, are as widely geographically distributed as the animals.

One way of trying to understand some of this variety is to look at exactly whereabouts on the artwork this DNA may have come from. The authors divide the drawings into four strata, the wooden base, the ‘preparation layer’ (including primer and preliminary sketch), the pigment layer, and the overlying varnish (Figure 2C in terms of main paper), and suggest that tree species such as Scots Pine and European Yew may be associated with the base; sheep glue, wheat starch primer and willow charcoal may be associated with the preparation layer; the pig and wolf could be from paintbrush hairs; and various micro-organisms associated with rodents and human skin could be surface accretions. [The wolf hair is a curious mistake. The species Canis lupus includes domestic dogs (strictly speaking Canis lupus familiaris), and ‘wolf-hair’ brushes are a) exclusively associated with Far East Asian art, and b) are not made of wolf hair, but weasel, the Chinese for which is “yellow mouse wolf.”]

Frankly I don’t think that’s helped very much.

Assuming that the identifications are sound, it seems that microscopical quantities of just about anything are found more or less everywhere, and tell us nothing. What might be more worthwhile would be to compare relative amounts. We would expect both a European artwork and a Judaean shroud to contain more dog than panda, and so it turns out. But in this respect there is little to distinguish a European artefact from a Judaean one. The most remarkable aspect of both studies is the distinct lack of animals or plants from the Middle East.