title: Developmental validation of the HIrisPlex system: DNA-based eye and hair colour prediction for forensic and anthropological usage.
abstract: Forensic DNA Phenotyping or 'DNA intelligence' tools are expected to aid police investigations and find unknown individuals by providing information on externally visible characteristics of unknown suspects, perpetrators and missing persons from biological samples. This is especially useful in cases where conventional DNA profiling or other means remain non-informative. Recently, we introduced the HIrisPlex system, capable of predicting both eye and hair colour from DNA. In the present developmental validation study, we demonstrate that the HIrisPlex assay performs in full agreement with the Scientific Working Group on DNA Analysis Methods (SWGDAM) guidelines providing an essential prerequisite for future HIrisPlex applications to forensic casework. The HIrisPlex assay produces complete profiles down to only 63 pg of DNA. Species testing revealed human specificity for a complete HIrisPlex profile, while only non-human primates showed the closest full profile at 20 out of the 24 DNA markers, in all animals tested. Rigorous testing of simulated forensic casework samples such as blood, semen, saliva stains, hairs with roots as well as extremely low quantity touch (trace) DNA samples, produced complete profiles in 88% of cases. Concordance testing performed between five independent forensic laboratories displayed consistent reproducible results on varying types of DNA samples. Due to its design, the assay caters for degraded samples, underlined here by results from artificially degraded DNA and from simulated casework samples of degraded DNA. This aspect was also demonstrated previously on DNA samples from human remains up to several hundreds of years old. With this paper, we also introduce enhanced eye and hair colour prediction models based on enlarged underlying databases of HIrisPlex genotypes and eye/hair colour phenotypes (eye colour: N = 9188 and hair colour: N = 1601). Furthermore, we present an online web-based system for individual eye and hair colour prediction from full and partial HIrisPlex DNA profiles. By demonstrating that the HIrisPlex assay is fully compatible with the SWGDAM guidelines, we provide the first forensically validated DNA test system for parallel eye and hair colour prediction now available to forensic laboratories for immediate casework application, including missing person cases. Given the robustness and sensitivity described here and in previous work, the HIrisPlex system is also suitable for analysing old and ancient DNA in anthropological and evolutionary studies.
authors: Department of Forensic Molecular Biology, Erasmus MC University Medical Centre Rotterdam, Rotterdam, The Netherlands.
authors: Susan
authors: S
authors: Walsh
authors: Department of Forensic Molecular Biology, Erasmus MC University Medical Centre Rotterdam, Rotterdam, The Netherlands.
authors: Lakshmi
authors: L
authors: Chaitanya
authors: Department of Human Biological Traces, Netherlands Forensic Institute, The Hague, The Netherlands.
authors: Lindy
authors: L
authors: Clarisse
authors: Forensic Laboratory for DNA Research, Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
authors: Laura
authors: L
authors: Wirken
authors: Section of Forensic Genetics, Institute of Forensic Research, Kraków, Poland.
authors: Jolanta
authors: J
authors: Draus-Barini
authors: Laboratory of Forensic Medicine & Toxicology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors: Leda
authors: L
authors: Kovatsi
authors: Department of Legal Medicine, Osaka City University, Medical School, Osaka, Japan.
authors: Hitoshi
authors: H
authors: Maeda
authors: Department of Legal Medicine, Osaka City University, Medical School, Osaka, Japan; Division of Legal Medicine, Faculty of Medicine, Tottori University, 86 Nichicho Yonago, Japan.
authors: Takaki
authors: T
authors: Ishikawa
authors: Department of Human Biological Traces, Netherlands Forensic Institute, The Hague, The Netherlands.
authors: Titia
authors: T
authors: Sijen
authors: Forensic Laboratory for DNA Research, Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
authors: Peter
authors: P
authors: de Knijff
authors: Section of Forensic Genetics, Institute of Forensic Research, Kraków, Poland; Department of Genetics and Evolution, Institute of Zoology, Jagiellonian University, Kraków, Poland.
authors: Wojciech
authors: W
authors: Branicki
authors: Department of Forensic Molecular Biology, Erasmus MC University Medical Centre Rotterdam, Rotterdam, The Netherlands.
authors: Fan
authors: F
authors: Liu
authors: Department of Forensic Molecular Biology, Erasmus MC University Medical Centre Rotterdam, Rotterdam, The Netherlands. Electronic address: m.kayser@erasmusmc.nl.
authors: Manfred
authors: M
authors: Kayser
mesh_terms: D000483:Alleles; D001774:Blood Chemical Analysis; D004247:DNA / Q000235:genetics* / Q000302:isolation & purification; D005127:Eye Color / Q000235:genetics*; D053803:Forensic Genetics; D005838:Genotype; D006197:Hair / Q000737:chemistry; D006200:Hair Color / Q000235:genetics*; D006579:Heterozygote; D006801:Humans; D020641:Polymorphism, Single Nucleotide; D012463:Saliva / Q000737:chemistry; D012661:Semen / Q000737:chemistry
chemical_list: D004247:DNA
keywords: Developmental validation; Eye colour prediction; Forensic DNA Phenotyping, FDP; HIrisPlex; Hair colour prediction; SNP; SWGDAM