title: Development of a forensic skin colour predictive test.
abstract: There is growing interest in skin colour prediction in the forensic field. However, a lack of consensus approaches for recording skin colour phenotype plus the complicating factors of epistatic effects, environmental influences such as exposure to the sun and unidentified genetic variants, present difficulties for the development of a forensic skin colour predictive test centred on the most strongly associated SNPs. Previous studies have analysed skin colour variation in single unadmixed population groups, including South Asians (Stokowski et al., 2007, Am. J. Hum. Genet, 81: 1119-32) and Europeans (Jacobs et al., 2013, Hum Genet. 132: 147-58). Nevertheless, a major challenge lies in the analysis of skin colour in admixed individuals, where co-ancestry proportions do not necessarily dictate any one person's skin colour. Our study sought to analyse genetic differences between African, European and admixed African-European subjects where direct spectrometric measurements and photographs of skin colour were made in parallel. We identified strong associations to skin colour variation in the subjects studied from a pigmentation SNP discovery panel of 59 markers and developed a forensic online classifier based on naïve Bayes analysis of the SNP profiles made. A skin colour predictive test is described using the ten most strongly associated SNPs in 8 genes linked to skin pigmentation variation.
authors.affiliation: Forensic Genetics Unit, Institute of Forensic Science "Luis Concheiro", University of Santiago de Compostela, Spain.
authors.forename: Olalla
authors.initials: O
authors.lastname: Maroñas
authors.affiliation: Forensic Genetics Unit, Institute of Forensic Science "Luis Concheiro", University of Santiago de Compostela, Spain. Electronic address: c.phillips@mac.com.
authors.forename: Chris
authors.initials: C
authors.lastname: Phillips
authors.affiliation: Forensic Genetics Unit, Institute of Forensic Science "Luis Concheiro", University of Santiago de Compostela, Spain.
authors.forename: Jens
authors.initials: J
authors.lastname: Söchtig
authors.affiliation: Faculty of Mathematics, University of Santiago de Compostela, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Gomez-Tato
authors.affiliation: CIBERER, Genomic Medicine Group, University of Santiago de Compostela, Spain.
authors.forename: Raquel
authors.initials: R
authors.lastname: Cruz
authors.affiliation: Faculty of Mathematics, University of Santiago de Compostela, Spain.
authors.forename: José
authors.initials: J
authors.lastname: Alvarez-Dios
authors.affiliation: Faculty of Mathematics, University of Santiago de Compostela, Spain.
authors.forename: María Casares
authors.initials: MC
authors.lastname: de Cal
authors.affiliation: Criminalistics Unit Against Violation of Fundamental Rights (UCCVDF-AMC), Public Ministry, Caracas, Venezuela.
authors.forename: Yarimar
authors.initials: Y
authors.lastname: Ruiz
authors.affiliation: Forensic Genetics Unit, Institute of Forensic Science "Luis Concheiro", University of Santiago de Compostela, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Fondevila
authors.affiliation: Forensic Genetics Unit, Institute of Forensic Science "Luis Concheiro", University of Santiago de Compostela, Spain; CIBERER, Genomic Medicine Group, University of Santiago de Compostela, Spain; Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Ángel
authors.initials: Á
authors.lastname: Carracedo
authors.affiliation: Forensic Genetics Unit, Institute of Forensic Science "Luis Concheiro", University of Santiago de Compostela, Spain.
authors.forename: María V
authors.initials: MV
authors.lastname: Lareu
mesh_terms: D000328:Adult; D000951:Antigens, Neoplasm / Q000235:genetics; D017920:Antiporters / Q000235:genetics; D044383:Black People / Q000235:genetics*; D005260:Female; D053803:Forensic Genetics; D005838:Genotype; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000235:genetics; D016013:Likelihood Functions; D016015:Logistic Models; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics; D026901:Membrane Transport Proteins / Q000235:genetics; D008875:Middle Aged; D010088:Oxidoreductases / Q000235:genetics; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D025341:Principal Component Analysis; D044102:Receptor, Melanocortin, Type 1 / Q000235:genetics; D012880:Skin Pigmentation / Q000235:genetics*; D044465:White People / Q000235:genetics*; D055815:Young Adult
chemical_list: D000951:Antigens, Neoplasm; D017920:Antiporters; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; C489600:OCA2 protein, human; D044102:Receptor, Melanocortin, Type 1; C506584:SLC24A5 protein, human; C510061:SLC45A2 protein, human; D010088:Oxidoreductases; C489799:TYRP1 protein, human; D019746:Intramolecular Oxidoreductases; C042501:dopachrome isomerase
keywords: Externally visible traits; Forensic phenotyping; Linear regression analysis; Naïve Bayes classification; Pigmentation; Skin colour prediction