title: Exploration of SNP variants affecting hair colour prediction in Europeans.
abstract: DNA profiling is a key tool for forensic analysis; however, current methods identify a suspect either by direct comparison or from DNA database searches. In cases with unidentified suspects, prediction of visible physical traits e.g. pigmentation or hair distribution of the DNA donors can provide important probative information. This study aimed to explore single nucleotide polymorphism (SNP) variants for their effect on hair colour prediction. A discovery panel of 63 SNPs consisting of already established hair colour markers from the HIrisPlex hair colour phenotyping assay as well as additional markers for which associations to human pigmentation traits were previously identified was used to develop multiplex assays based on SNaPshot single-base extension technology. A genotyping study was performed on a range of European populations (n = 605). Hair colour phenotyping was accomplished by matching donor's hair to a graded colour category system of reference shades and photography. Since multiple SNPs in combination contribute in varying degrees to hair colour predictability in Europeans, we aimed to compile a compact marker set that could provide a reliable hair colour inference from the fewest SNPs. The predictive approach developed uses a naïve Bayes classifier to provide hair colour assignment probabilities for the SNP profiles of the key SNPs and was embedded into the Snipper online SNP classifier ( http://mathgene.usc.es/snipper/ ). Results indicate that red, blond, brown and black hair colours are predictable with informative probabilities in a high proportion of cases. Our study resulted in the identification of 12 most strongly associated SNPs to hair pigmentation variation in six genes.
authors.affiliation: Forensic Genetics Unit, Institute of Legal Medicine, University of Santiago de Compostela, A Coruña, Spain.
authors.forename: Jens
authors.initials: J
authors.lastname: Söchtig
authors.forename: Chris
authors.initials: C
authors.lastname: Phillips
authors.forename: Olalla
authors.initials: O
authors.lastname: Maroñas
authors.forename: Antonio
authors.initials: A
authors.lastname: Gómez-Tato
authors.forename: Raquel
authors.initials: R
authors.lastname: Cruz
authors.forename: Jose
authors.initials: J
authors.lastname: Alvarez-Dios
authors.forename: María-Ángeles Casares
authors.initials: MÁ
authors.lastname: de Cal
authors.forename: Yarimar
authors.initials: Y
authors.lastname: Ruiz
authors.forename: Kristian
authors.initials: K
authors.lastname: Reich
authors.forename: Manuel
authors.initials: M
authors.lastname: Fondevila
authors.forename: Ángel
authors.initials: Á
authors.lastname: Carracedo
authors.forename: María V
authors.initials: MV
authors.lastname: Lareu
mesh_terms: D005060:Europe; D005260:Female; D005819:Genetic Markers; D005838:Genotype; D006200:Hair Color / Q000235:genetics*; D006801:Humans; D016013:Likelihood Functions; D016015:Logistic Models; D008297:Male; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D044465:White People / Q000235:genetics*
chemical_list: D005819:Genetic Markers