Assessment of IrisPlex-based multiplex for eye and skin color prediction with application to a Portuguese population.
DNA phenotyping research is one of the most emergent areas of forensic genetics. Predictions of externally visible characteristics are possible through analysis of single nucleotide polymorphisms. These tools can provide police with "intelligence" in cases where there are no obvious suspects and unknown biological samples found at the crime scene do not result in any criminal DNA database hits. IrisPlex, an eye color prediction assay, revealed high prediction rates for blue and brown eye color in European populations. However, this is less predictive in some non-European populations, probably due to admixing. When compared to other European countries, Portugal has a relatively admixed population, resulting from a genetic influx derived from its proximity to and historical relations with numerous African territories. The aim of this work was to evaluate the utility of IrisPlex in the Portuguese population. Furthermore, the possibility of supplementing this multiplex with additional markers to also achieve skin color prediction within this population was evaluated. For that, IrisPlex was augmented with additional SNP loci. Eye and skin color prediction was estimated using the multinomial logistic regression and binomial logistic regression models, respectively. The results demonstrated eye color prediction accuracies of the IrisPlex system of 90 and 60% for brown and blue eye color, respectively, and 77% for intermediate eye color, after allele frequency adjustment. With regard to skin color, it was possible to achieve a prediction accuracy of 93%. In the future, phenotypic determination multiplexes must include additional loci to permit skin color prediction as presented in this study as this can be an advantageous tool for forensic investigation.
INMLCF - National Institute of Legal Medicine and Forensic Sciences, Largo da Sé Nova, 3000-213, Coimbra, Portugal. pdario@dlinml.mj.pt.|Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016, Lisboa, Portugal. pdario@dlinml.mj.pt.|CENCIFOR - Forensic Sciences Centre, Largo da Sé Nova, 3000-213, Coimbra, Portugal. pdario@dlinml.mj.pt.|CESAM - Centre for Environmental and Marine Studies, Edifício C2, Campo Grande, 1749-016, Lisboa, Portugal. pdario@dlinml.mj.pt.
Paulo
P
Dario
Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016, Lisboa, Portugal.
Helena
H
Mouriño
Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016, Lisboa, Portugal.|CESAM - Centre for Environmental and Marine Studies, Edifício C2, Campo Grande, 1749-016, Lisboa, Portugal.
Ana Rita
AR
Oliveira
INMLCF - National Institute of Legal Medicine and Forensic Sciences, Largo da Sé Nova, 3000-213, Coimbra, Portugal.
Isabel
I
Lucas
INMLCF - National Institute of Legal Medicine and Forensic Sciences, Largo da Sé Nova, 3000-213, Coimbra, Portugal.|CENCIFOR - Forensic Sciences Centre, Largo da Sé Nova, 3000-213, Coimbra, Portugal.
Teresa
T
Ribeiro
INMLCF - National Institute of Legal Medicine and Forensic Sciences, Largo da Sé Nova, 3000-213, Coimbra, Portugal.|CENCIFOR - Forensic Sciences Centre, Largo da Sé Nova, 3000-213, Coimbra, Portugal.
Maria João
MJ
Porto
INMLCF - National Institute of Legal Medicine and Forensic Sciences, Largo da Sé Nova, 3000-213, Coimbra, Portugal.|CENCIFOR - Forensic Sciences Centre, Largo da Sé Nova, 3000-213, Coimbra, Portugal.|Faculty of Medicine, University of Lisbon, Av. Professor Egas Moniz, 1649-028, Lisboa, Portugal.
Jorge
J
Costa Santos
Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016, Lisboa, Portugal.|CESAM - Centre for Environmental and Marine Studies, Edifício C2, Campo Grande, 1749-016, Lisboa, Portugal.
Deodália
D
Dias
INMLCF - National Institute of Legal Medicine and Forensic Sciences, Largo da Sé Nova, 3000-213, Coimbra, Portugal.|CENCIFOR - Forensic Sciences Centre, Largo da Sé Nova, 3000-213, Coimbra, Portugal.|Faculty of Medicine, University of Coimbra, Rua Larga, 3004-504, Coimbra, Portugal.
Francisco
F
Corte Real
D000293:Adolescent; D000328:Adult; D000368:Aged; D000951:Antigens, Neoplasm / Q000235:genetics; D017920:Antiporters / Q000235:genetics; D005127:Eye Color / Q000235:genetics*; D005260:Female; D053803:Forensic Genetics; D005828:Genetics, Population; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics; D006801:Humans; D050835:Interferon Regulatory Factors / Q000235:genetics; D016015:Logistic Models; D008297:Male; D026901:Membrane Transport Proteins / Q000235:genetics; D008875:Middle Aged; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D011174:Portugal; D011237:Predictive Value of Tests; D060888:Real-Time Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D012880:Skin Pigmentation / Q000235:genetics*; D044767:Ubiquitin-Protein Ligases; D055815:Young Adult; D000099218:Interferon Regulatory Factor-4
D000951:Antigens, Neoplasm; D017920:Antiporters; D020662:Guanine Nucleotide Exchange Factors; D050835:Interferon Regulatory Factors; D026901:Membrane Transport Proteins; D044767:Ubiquitin-Protein Ligases; D000099218:Interferon Regulatory Factor-4; C489600:OCA2 protein, human; C470570:SLC24A4 protein, human; C510061:SLC45A2 protein, human; C118566:HERC2 protein, human
EVC; Eye color prediction; Forensic DNA phenotyping; IrisPlex; Multinomial logistic regression; Skin color prediction