Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry combined with multidimensional scaling, binary hierarchical cluster tree and selected diagnostic masses improves species identification of Neolithic keratin sequences from furs of the Tyrolean Iceman Oetzi

Abstract

The identification of fur origins from the 5300-year-old Tyrolean Iceman's accoutrement is not yet complete, although definite identification is essential for the socio-cultural context of his epoch. Neither have all potential samples been identified so far, nor there has a consensus been reached on the species identified using the classical methods. Archaeological hair often lacks analyzable hair scale patterns in microscopic analyses and polymer chain reaction (PCR)-based techniques are often inapplicable due to the lack of amplifiable ancient DNA. To overcome these drawbacks, a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) method was used exclusively based on hair keratins. Thirteen fur specimens from his accoutrement were analyzed after tryptic digest of native hair. Peptide mass fingerprints (pmfs) from ancient samples and from reference species mostly occurring in the Alpine surroundings at his lifetime were compared to each other using multidimensional scaling and binary hierarchical cluster tree analysis. Both statistical methods highly reflect spectral similarities among pmfs as close zoological relationships. While multidimensional scaling was useful to discriminate specimens on the zoological order level, binary hierarchical cluster tree reached the family or subfamily level. Additionally, the presence and/or absence of order, family and/or species-specific diagnostic masses in their pmfs allowed the identification of mammals mostly down to single species level. Red deer was found in his shoe vamp, goat in the leggings, cattle in his shoe sole and at his quiver's closing flap as well as sheep and chamois in his coat. Canid species, like grey wolf, domestic dog or European red fox, were discovered in his leggings for the first time, but could not be differentiated to species level. This is widening the spectrum of processed fur-bearing species to at least one member of the Canidae family. His fur cap was allocated to a carnivore species, but differentiation between brown bear and a canid species could not be made with certainty.

Species Identification of Archaeological Skin Objects from Danish Bogs: Comparison between Mass Spectrometry-Based Peptide Sequencing and Microscopy-Based Methods

“…Only a limited number of the species-specific peptides identified (Fig. 2 and Table S5 in File S1), were previously reported in literature describing ancient samples [43], [46]–[49], [63].…”

Chemometrics reveals oil sources in the Fangzheng Fault Depression, NE China

“…MDS has already been used to evaluate data from many disciplines (Shi et al, 2000;Lenz and Foran, 2010;Hollemeyer et al, 2012), including biomarker data (Revill et al, 1992;Zhou et al, 2015). Classical MDS generally uses the Euclidean distance to distinguish data sets, http://dx.doi.org/10.1016/j.orggeochem.2016.09.008 0146-6380/Ó 2016 Elsevier Ltd. All rights reserved.…”

Positioning the Red Deer (Cervus elaphus) Hunted by the Tyrolean Iceman into a Mitochondrial DNA Phylogeny

“…Early studies were conducted in the 1990s and were designed to molecular analyze samples of grass most likely coming from the shoes and the cape of Ötzi [1], [2]. Later, studies carried out through matrix-assisted laser desorption/ionization time-of-flight mass spectrometric (MALDI-TOF MS) method and microscopy analyzed fur specimens from the accoutrement and detected chamois, brown bear, goat, cattle, canid species, sheep and red deer [3]–[5]. In 2012 Olivieri et al, [6] identified and sequenced mitochondrial DNA (mtDNA) fragments of sheep ( Ovis aries ) from black animal hair shafts recovered from Ötzi's clothes.…”