title: Collaborative genetic mapping of 12 forensic short tandem repeat (STR) loci on the human X chromosome.
abstract: A large number of short tandem repeat (STR) markers spanning the entire human X chromosome have been described and established for use in forensic genetic testing. Due to their particular mode of inheritance, X-STRs often allow easy and informative haplotyping in kinship analyses. Moreover, some X-STRs are known to be tightly linked so that, in combination, they constitute even more complex genetic markers than each STR taken individually. As a consequence, X-STRs have proven particularly powerful in solving complex cases of disputed blood relatedness. However, valid quantification of the evidence provided by X-STR genotypes in the form of likelihood ratios requires that the recombination rates between markers are exactly known. In a collaborative family study, we used X-STR genotype data from 401 two- and three-generation families to derive valid estimates of the recombination rates between 12 forensic markers widely used in forensic testing, namely DXS10148, DXS10135, DXS8378 (together constituting linkage group I), DXS7132, DXS10079, DXS10074 (linkage group II), DXS10103, HPRTB, DXS10101 (linkage group III), DXS10146, DXS10134 and DXS7423 (linkage group IV). Our study is the first to simultaneously allow for mutation and recombination in the underlying likelihood calculations, thereby obviating the bias-prone practice of excluding ambiguous transmission events from further consideration. The statistical analysis confirms that linkage groups I and II are transmitted independently from one another whereas linkage groups II, III and IV are characterised by inter-group recombination fractions that are notably smaller than 50%. Evidence was also found for recombination within all four linkage groups, with recombination fraction estimates ranging as high as 2% in the case of DXS10146 and DXS10134.
authors.affiliation: Institut für Medizinische Informatik und Statistik, Christian-Albrechts-Universität Kiel, Brunswiker Straße 10, 24105 Kiel, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Nothnagel
authors.forename: Reinhard
authors.initials: R
authors.lastname: Szibor
authors.forename: Oliver
authors.initials: O
authors.lastname: Vollrath
authors.forename: Christa
authors.initials: C
authors.lastname: Augustin
authors.forename: Jeanett
authors.initials: J
authors.lastname: Edelmann
authors.forename: Maria
authors.initials: M
authors.lastname: Geppert
authors.forename: Cíntia
authors.initials: C
authors.lastname: Alves
authors.forename: Leonor
authors.initials: L
authors.lastname: Gusmão
authors.forename: Marielle
authors.initials: M
authors.lastname: Vennemann
authors.forename: Yiping
authors.initials: Y
authors.lastname: Hou
authors.forename: Uta-Dorothee
authors.initials: UD
authors.lastname: Immel
authors.forename: Serena
authors.initials: S
authors.lastname: Inturri
authors.forename: Haibo
authors.initials: H
authors.lastname: Luo
authors.forename: Sabine
authors.initials: S
authors.lastname: Lutz-Bonengel
authors.forename: Carlo
authors.initials: C
authors.lastname: Robino
authors.forename: Lutz
authors.initials: L
authors.lastname: Roewer
authors.forename: Burkhard
authors.initials: B
authors.lastname: Rolf
authors.forename: Juliane
authors.initials: J
authors.lastname: Sanft
authors.forename: Kyoung-Jin
authors.initials: KJ
authors.lastname: Shin
authors.forename: Jeong Eun
authors.initials: JE
authors.lastname: Sim
authors.forename: Peter
authors.initials: P
authors.lastname: Wiegand
authors.forename: Christian
authors.initials: C
authors.lastname: Winkler
authors.forename: Michael
authors.initials: M
authors.lastname: Krawczak
authors.forename: Sandra
authors.initials: S
authors.lastname: Hering
mesh_terms: D002874:Chromosome Mapping / Q000379:methods*; D041321:Chromosomes, Human, X; D016172:DNA Fingerprinting / Q000379:methods*; D056426:Genetic Loci; D005838:Genotype; D006239:Haplotypes; D006801:Humans; D016013:Likelihood Functions; D018895:Microsatellite Repeats; D060885:Multiplex Polymerase Chain Reaction