title: Human mitochondrial DNA and nuclear DNA isolation from food bite marks.
abstract: OBJECTIVE
  Bite mark analysis is used for comparison between bite marks on a bitten object and the suspects' teeth. However, if it is not possible to obtain a correct match, it is important to recover salivary DNA. Previous studies have tried to isolate human nuclear DNA from bitten foods but were not completely successful. In the present work, we studied the efficiency of human nuclear and mitochondrial DNA isolation from bite marks in cheese, a donut and an apple.
  
  
  METHODS
  Using a double swab technique and silica-based DNA extraction kit, nuclear and mitochondrial DNA were isolated. Human housekeeping genes were amplified to analyse the efficiency of nuclear DNA profiling. mtDNA was sequencing and haplogroup assign.
  
  
  RESULTS
  Although cheese and apple samples showed the highest concentration of DNA, the purity of DNA on the apple was low. Moreover, apple samples failed to amplify the two human housekeeping genes, GAPDH and RPL22. In contrast, cheese samples have high purity and amplification efficiency. Donut samples showed an intermediate value and low amplification efficiency. In spite of these results, isolation and characterization/sequencing of human mitochondrial DNA was completely successful in the three samples, which pointed out the possibility of identification through this type of DNA.
  
  
  CONCLUSIONS
  This research indicated that it is possible to recover and isolate human nuclear and mitochondrial DNA from bitten foods, although the quantity and purity of nuclear DNA depends on the type of food. That is of significance important in forensic sciences for the correct identification of a suspect.
authors.affiliation: Department of Anthropology, NMNH-MRC 112, Smithsonian Institution, Washington, DC, 20013-7020, USA. Electronic address: Casado-Zapicos@si.edu.
authors.forename: Sara
authors.initials: S
authors.lastname: C Zapico
authors.affiliation: Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Hospital Universitario Central de Asturias (HUCA) and University of Oviedo, Oviedo, Asturias, 33006, Spain. Electronic address: sofiatirados@googlemail.com.
authors.forename: Sofía T
authors.initials: ST
authors.lastname: Menéndez
mesh_terms: D000328:Adult; D001734:Bites, Human / Q000235:genetics*; D016172:DNA Fingerprinting / Q000379:methods; D004272:DNA, Mitochondrial / Q000302:isolation & purification*; D005504:Food Analysis / Q000379:methods*; D005553:Forensic Dentistry / Q000379:methods*; D006801:Humans; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D004272:DNA, Mitochondrial
keywords: Food bite marks; Haplogroup; Human nuclear DNA isolation; PCR efficiency; Sequencing; mtDNA