title: Results of the 1999-2000 collaborative exercise and proficiency testing program on mitochondrial DNA of the GEP-ISFG: an inter-laboratory study of the observed variability in the heteroplasmy level of hair from the same donor.
abstract: The Spanish and Portuguese working group (GEP) of international society for forensic genetics (ISFG) 1999-2000 collaborative exercise on mitochondrial DNA (mtDNA) included the analysis of four bloodstain samples and one hair shaft sample by 19 participating laboratories from Spain, Portugal and several Latin-American countries. A wide range of sequence results at position 16,093 of the HV1 (from T or C homoplasmy to different levels of heteroplasmy) were submitted by the different participating laboratories from the hair shaft sample during the first phase of this exercise. During the discussion of these results in the Annual GEP-ISFG 2000 Conference a second phase of this exercise was established with two main objectives: (i) to evaluate the incidence of the HV1 sequence heteroplasmy detected in Phase I across different sample types from the same donor including blood, saliva, and hair shafts, (ii) to perform a technical review of the electropherograms to evaluate the relative levels of heteroplasmies obtained by the different laboratories and also to examine the source of possible errors detected in Phase I. Anonymous review of the raw sequence data permitted the detection of three transcription errors and three errors due to methodological problems. Highly variable levels of heteroplasmy were found in the hair shaft and more stability in blood and saliva. Three laboratories found variable levels of heteroplasmy at position 16,093 across adjacent fragments from the same hair shaft. Two laboratories also described more than one heteroplasmic position from a single hair. The relevance of these findings for the interpretation of mtDNA data in the forensic context is also discussed.
authors.affiliation: Departamento de Madrid, Instituto de Toxicología, Sección de Biología, Luis Cabrera 9, 28002 Madrid, Spain. biologia@mad.inaltox.es
authors.forename: Antonio
authors.initials: A
authors.lastname: Alonso
authors.forename: Antonio
authors.initials: A
authors.lastname: Salas
authors.forename: Cristina
authors.initials: C
authors.lastname: Albarrán
authors.forename: Eduardo
authors.initials: E
authors.lastname: Arroyo
authors.forename: Azucena
authors.initials: A
authors.lastname: Castro
authors.forename: Manuel
authors.initials: M
authors.lastname: Crespillo
authors.forename: Ana María
authors.initials: AM
authors.lastname: di Lonardo
authors.forename: María Victoria
authors.initials: MV
authors.lastname: Lareu
authors.forename: Carlos López
authors.initials: CL
authors.lastname: Cubría
authors.forename: Manuel López
authors.initials: ML
authors.lastname: Soto
authors.forename: José A
authors.initials: JA
authors.lastname: Lorente
authors.forename: Marta Montesino
authors.initials: MM
authors.lastname: Semper
authors.forename: Ana
authors.initials: A
authors.lastname: Palacio
authors.forename: Manuel
authors.initials: M
authors.lastname: Paredes
authors.forename: Luisa
authors.initials: L
authors.lastname: Pereira
authors.forename: Anna Pérez
authors.initials: AP
authors.lastname: Lezaun
authors.forename: José Pestano
authors.initials: JP
authors.lastname: Brito
authors.forename: Andrea
authors.initials: A
authors.lastname: Sala
authors.forename: María Conceiçao
authors.initials: MC
authors.lastname: Vide
authors.forename: Martín
authors.initials: M
authors.lastname: Whittle
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Yunis
authors.forename: Josefina
authors.initials: J
authors.lastname: Gómez
mesh_terms: D001801:Blood Stains; D019411:Clinical Laboratory Techniques / Q000592:standards*; D004272:DNA, Mitochondrial / Q000097:blood / Q000737:chemistry / Q000235:genetics*; D005554:Forensic Medicine / Q000379:methods*; D005819:Genetic Markers; D006197:Hair / Q000737:chemistry*; D006801:Humans; D007373:Interinstitutional Relations; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D011174:Portugal; D011786:Quality Control; D015203:Reproducibility of Results
chemical_list: D004272:DNA, Mitochondrial; D005819:Genetic Markers