title: Results of the 2003-2004 GEP-ISFG collaborative study on mitochondrial DNA: focus on the mtDNA profile of a mixed semen-saliva stain.
abstract: We report here a review of the seventh mitochondrial DNA (mtDNA) exercise undertaken by the Spanish and Portuguese working group (GEP) of the International Society for Forensic Genetics (ISFG) corresponding to the period 2003-2004. Five reference bloodstains from five donors (M1-M5), a mixed stain of saliva and semen (M6), and a hair sample (M7) were submitted to each participating laboratory for nuclear DNA (nDNA; autosomal STR and Y-STR) and mtDNA analysis. Laboratories were asked to investigate the contributors of samples M6 and M7 among the reference donors (M1-M5). A total of 34 laboratories reported total or partial mtDNA sequence data from both, the reference bloodstains (M1-M5) and the hair sample (M7) concluding a match between mtDNA profiles of M5 and M7. Autosomal STR and Y-STR profiling was the preferred strategy to investigate the contributors of the semen/saliva mixture (M6). Nuclear DNA profiles were consistent with a mixture of saliva from the donor (female) of M4 and semen from donor M5, being the semen (XY) profile the dominant component of the mixture. Strikingly, and in contradiction to the nuclear DNA analysis, mtDNA sequencing results yield a more simple result: only the saliva contribution (M4) was detected, either after preferential lysis or after complete DNA digestion. Some labs provided with several explanations for this finding and carried out additional experiments to explain this apparent contradictory result. The results pointed to the existence of different relative amounts of nuclear and mtDNAs in saliva and semen. We conclude that this circumstance could strongly influence the interpretation of the mtDNA evidence in unbalanced mixtures and in consequence lead to false exclusions. During the GEP-ISFG annual conference a validation study was planned to progress in the interpretation of mtDNA from different mixtures.
authors.affiliation: Instituto Nacional de Toxicología y Ciencias Forenses, Servicio de Biología, Barcelona, Spain. manuel.crespillo@mju.es
authors.forename: Manuel
authors.initials: M
authors.lastname: Crespillo
authors.forename: Miguel R
authors.initials: MR
authors.lastname: Paredes
authors.forename: Lourdes
authors.initials: L
authors.lastname: Prieto
authors.forename: Marta
authors.initials: M
authors.lastname: Montesino
authors.forename: Antonio
authors.initials: A
authors.lastname: Salas
authors.forename: Cristina
authors.initials: C
authors.lastname: Albarran
authors.forename: V
authors.initials: V
authors.lastname: Alvarez-Iglesias
authors.forename: Antonio
authors.initials: A
authors.lastname: Amorin
authors.forename: Gemma
authors.initials: G
authors.lastname: Berniell-Lee
authors.forename: Antonio
authors.initials: A
authors.lastname: Brehm
authors.forename: Juan C
authors.initials: JC
authors.lastname: Carril
authors.forename: Daniel
authors.initials: D
authors.lastname: Corach
authors.forename: Nerea
authors.initials: N
authors.lastname: Cuevas
authors.forename: Ana M
authors.initials: AM
authors.lastname: Di Lonardo
authors.forename: Christian
authors.initials: C
authors.lastname: Doutremepuich
authors.forename: Rosa M
authors.initials: RM
authors.lastname: Espinheira
authors.forename: Marta
authors.initials: M
authors.lastname: Espinoza
authors.forename: Felix
authors.initials: F
authors.lastname: Gómez
authors.forename: Alberto
authors.initials: A
authors.lastname: González
authors.forename: Alexis
authors.initials: A
authors.lastname: Hernández
authors.forename: M
authors.initials: M
authors.lastname: Hidalgo
authors.forename: Magda
authors.initials: M
authors.lastname: Jimenez
authors.forename: Fabio P N
authors.initials: FP
authors.lastname: Leite
authors.forename: Ana M
authors.initials: AM
authors.lastname: López
authors.forename: Manuel
authors.initials: M
authors.lastname: López-Soto
authors.forename: Jose A
authors.initials: JA
authors.lastname: Lorente
authors.forename: Shintia
authors.initials: S
authors.lastname: Pagano
authors.forename: Ana M
authors.initials: AM
authors.lastname: Palacio
authors.forename: José J
authors.initials: JJ
authors.lastname: Pestano
authors.forename: Maria F
authors.initials: MF
authors.lastname: Pinheiro
authors.forename: Eduardo
authors.initials: E
authors.lastname: Raimondi
authors.forename: M M
authors.initials: MM
authors.lastname: Ramón
authors.forename: Florangel
authors.initials: F
authors.lastname: Tovar
authors.forename: Lidia
authors.initials: L
authors.lastname: Vidal-Rioja
authors.forename: Maria C
authors.initials: MC
authors.lastname: Vide
authors.forename: Martín R
authors.initials: MR
authors.lastname: Whittle
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Yunis
authors.forename: Julia
authors.initials: J
authors.lastname: Garcia-Hirschfel
mesh_terms: D019411:Clinical Laboratory Techniques / Q000592:standards*; D016172:DNA Fingerprinting / Q000592:standards; D004272:DNA, Mitochondrial / Q000097:blood / Q000235:genetics*; D005260:Female; D006197:Hair / Q000737:chemistry; D006801:Humans; D008297:Male; D011786:Quality Control; D012463:Saliva / Q000737:chemistry*; D012661:Semen / Q000737:chemistry*; D017422:Sequence Analysis, DNA; D012955:Societies, Medical
chemical_list: D004272:DNA, Mitochondrial