The “neolithic” microbial flora of the Iceman’s grass: morphological description and DNA analysis

Abstract

The analysis of the DNA found in the grass fragments from the “cloak” and “Snow footwear” worn by the Iceman has offered interesting insights into the long-term preservation of DNA and useful molecular clues to the grass species utilized by neolithic men to manufacture their equipment (see “DNA analysis of the grass remains found at the Iceman’s archaeological site”, this volume). The results of the analyses, however, have also posed a number of puzzling questions by showing that a relevant fraction of the DNA extracted from the grass is made up of “foreign” double helices which may come from the genetic material of unicellular algae, fungi, bacteria and even land plants other than grasses. A preliminary survey of three fragments of the ancient grass using a scanning electron microscope (SEM) aimed at verifying whether anything resembling a filamentous fungus or a unicellular alga was associated with the grass, showed that, actually, fungal hyphae were present in one sample out of three. The distribution and length of the hyphae suggested that they could belong to a plant parasite which was already present on the grass when it was harvested 5,300 years ago rather than to a modern saprophyte which colonized the archaeological specimens following their recovery from the glacier.