title: Amino acid racemization and the preservation of ancient DNA.
abstract: The extent of racemization of aspartic acid, alanine, and leucine provides criteria for assessing whether ancient tissue samples contain endogenous DNA. In samples in which the D/L ratio of aspartic acid exceeds 0.08, ancient DNA sequences could not be retrieved. Paleontological finds from which DNA sequences purportedly millions of years old have been reported show extensive racemization, and the amino acids present are mainly contaminates. An exception is the amino acids in some insects preserved in amber.
authors.affiliation: University of Munich, Germany.
authors.forename: H N
authors.initials: HN
authors.lastname: Poinar
authors.forename: M
authors.initials: M
authors.lastname: Höss
authors.forename: J L
authors.initials: JL
authors.lastname: Bada
authors.forename: S
authors.initials: S
authors.lastname: Pääbo
mesh_terms: D000409:Alanine / Q000737:chemistry; D018647:Amber / Q000737:chemistry; D000596:Amino Acids / Q000737:chemistry*; D000818:Animals; D001224:Aspartic Acid / Q000737:chemistry; D004247:DNA / Q000032:analysis* / Q000737:chemistry; D005580:Fossils; D049690:History, Ancient; D006801:Humans; D007930:Leucine / Q000737:chemistry; D010163:Paleontology; D013237:Stereoisomerism
chemical_list: D018647:Amber; D000596:Amino Acids; D001224:Aspartic Acid; D004247:DNA; D007930:Leucine; D000409:Alanine