title: miRNAs in Ancient Tissue Specimens of the Tyrolean Iceman.
abstract: The analysis of nucleic acids in ancient samples is largely limited to DNA. Small noncoding RNAs (microRNAs) are known to be evolutionary conserved and stable. To gain knowledge on miRNAs measured from ancient samples, we profiled microRNAs in cryoconserved mummies. First, we established the approach on a World War One warrior, the "Kaiserjäger", which has been preserved for almost one century. Then, we profiled seven ancient tissue specimens including skeletal muscle, stomach mucosa, stomach content and two corpus organ tissues of the 5,300-year-old copper age mummy Iceman and compared these profiles to the presence of organ-specific miRNAs in modern tissues. Our analyses suggest the presence of specific miRNAs in the different Iceman's tissues. Of 1,066 analyzed human miRNAs, 31 were discovered across all biopsies and 87 miRNAs were detected only in a single sample. To check for potential microbiological contaminations, all miRNAs detected in Iceman samples and not present in ancient samples were mapped to 14,582 bacterial and viral genomes. We detected few hits (3.9% of miRNAs compared with 3.6% of miRNAs). Interestingly, the miRNAs with higher abundance across all ancient tissues were significantly enriched for Guanine (P value of 10-13) and Cytosine (P value of 10-7). The same pattern was observed for modern tissues. Comparing miRNAs measured from ancient organs to modern tissue patterns highlighted significant similarities, e.g., for miRNAs present in the muscle. Our first comprehensive analysis of microRNAs in ancient human tissues indicates that these stable molecules can be detected in tissue specimens after 5,300 years.
authors.affiliation: Department of Clinical Bioinformatics, Medical Faculty, Saarland University, Saarbrücken, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Keller
authors.affiliation: Life Sciences Research Unit (LSRU), Signal Transduction Laboratory, University of Luxembourg, Belvaux, Luxembourg.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Kreis
authors.affiliation: Medical Faculty, Institute of Human Genetics, Saarland University, Homburg, Germany.
authors.forename: Petra
authors.initials: P
authors.lastname: Leidinger
authors.affiliation: Institute for Mummies and the Iceman, European Academy of Bozen/Bolzano (EURAC), Bolzano, Italy.
authors.forename: Frank
authors.initials: F
authors.lastname: Maixner
authors.affiliation: Medical Faculty, Institute of Human Genetics, Saarland University, Homburg, Germany.
authors.forename: Nicole
authors.initials: N
authors.lastname: Ludwig
authors.affiliation: Department of Clinical Bioinformatics, Medical Faculty, Saarland University, Saarbrücken, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Backes
authors.affiliation: Department of Clinical Bioinformatics, Medical Faculty, Saarland University, Saarbrücken, Germany.
authors.forename: Valentina
authors.initials: V
authors.lastname: Galata
authors.affiliation: Environmental Research and Innovation (ERIN), Luxembourg Institute of Science and Technology (LIST), Esch/Alzette, Luxembourg.
authors.forename: Gea
authors.initials: G
authors.lastname: Guerriero
authors.affiliation: Department of Clinical Bioinformatics, Medical Faculty, Saarland University, Saarbrücken, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Fehlmann
authors.affiliation: Institute of Clinical Molecular Biology, Christian-Albrechts-University of Kiel, Kiel, Germany.
authors.forename: Andre
authors.initials: A
authors.lastname: Franke
authors.affiliation: Internal Medicine III, Heidelberg University, Heidelberg, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Meder
authors.affiliation: Institute for Mummies and the Iceman, European Academy of Bozen/Bolzano (EURAC), Bolzano, Italy.
authors.forename: Albert
authors.initials: A
authors.lastname: Zink
authors.affiliation: Medical Faculty, Institute of Human Genetics, Saarland University, Homburg, Germany.
authors.forename: Eckart
authors.initials: E
authors.lastname: Meese
mesh_terms: D000072441:DNA, Ancient / Q000032:analysis*; D006801:Humans; D035683:MicroRNAs / Q000032:analysis / Q000235:genetics*; D009106:Mummies; D021141:Nucleic Acid Amplification Techniques / Q000379:methods
chemical_list: D000072441:DNA, Ancient; D035683:MicroRNAs
keywords: Iceman; ancient; miRNA