New genes involved in human eye color identified

Three new genetic loci have been identified with involvement in subtle and quantitative variation of human eye colour. The study, led by Manfred Kayser of the Erasmus University Medical Center Rotterdam, The Netherlands, is published May 6 in the open-access journal PLoS Genetics.

Previous studies on the genetics of human eye colour used broadly-categorized trait information such as 'blue', 'green', and 'brown'; however, variation in eye colour exists in a continuous grading from the lightest blue to the darkest brown. In this genome-wide association study, the eye colour of about 6000 Dutch Europeans from the Rotterdam Study was digitally quantified using high-resolution full-eye photographs. This quantitative approach, which is cost-effective, portable, and time efficient, revealed that human eye colour varies along more dimensions than are represented by the colour categories used previously.

The researchers identified three new loci significantly associated with quantitative eye colour. One of these, the LYST gene, was previously considered a pigmentation gene in mice and cattle, whereas the other two had no previous association with pigmentation.

These three genes, together with previously identified ones, explained over 50% of eye colour variance, representing the highest accuracy achieved so far in genomic prediction of complex and quantitative human traits.

"These findings are also of relevance for future forensic applications", said Kayser, "where appearance prediction from biological material found at crime scenes may provide investigative leads to trace unknown persons".

FINANCIAL DISCLOSURE: The Rotterdam Study authors acknowledge funding from the Netherlands Genomics Initiative (NGI) and Netherlands Organization for Scientific Research (NWO) (nr. 050-060-810) within the framework of the Forensic Genomics Consortium Netherlands (FGCN), the Netherlands Forensic Institute and the Research Institute for Diseases in the Elderly (RIDE) (nr. 014-93-015). The generation and management of GWAS genotype data for the Rotterdam Study (RS-I, RS-II) was supported by a NWO investments grant (nr. 175.010.2005.011, 911-03-012). The Rotterdam Study is funded by the Erasmus University Medical Center, Erasmus University Rotterdam; the Netherlands Organization for the Health Research and Development (ZonMw); the RIDE; the Ministry of Education, Culture, and Science; the Ministry for Health, Welfare, and Sports of the Netherlands; the European Commission (DG XII); and the Municipality of Rotterdam. The ophthalmic part of the Rotterdam Study was supported by Lijf en Leven, Krimpen, and Lek; MD Fonds, Utrecht. Oogfonds Nederland, Utrecht; Stichting Nederlands Oogheelkundig Onderzoek, Nijmegen, Rotterdam; Swart van Essen, Rotterdam; NWO; Bevordering van Volkskracht, Rotterdam; Blindenhulp, The Hague; Rotterdamse Vereniging Blindenbelangen, Rotterdam; OOG, The Hague; Algemene Nederlandse Vereniging ter Voorkoming van Blindheid, Doorn; Blinden-Penning, Amsterdam; Blindenhulp, Gravenzande; Henkes Stichting, Rotterdam; Topcon Europe BV, Capelle aan de IJssel; Medical Workshop BV, Groningen (all in the Netherlands); as well as Heidelberg Engineering, Dossenheim, Germany. The TwinsUK authors acknowledge funding from the Wellcome Trust, the EU MyEuropia Marie Curie Research Training Network, Guide Dogs for the Blind Association the European Community's Seventh Framework Programme (FP7 2007-2013)/grant agreement HEALTH-F2-2008-201865-GEFOS and (FP7 2007-2013), ENGAGE project grant agreement HEALTH-F4-2007-201413, and the FP-5 GenomEUtwin Project (QLG2-CT-2002-01254). The study also receives support from the Department of Health via the National Institute for Health Research (NIHR) comprehensive Biomedical Research Centre award to Guys St Thomas NHS Foundation Trust in partnership with Kings College London. TDS is an NIHR senior Investigator and CJH an NIHR Senior Research Fellow. The project also received support from a Biotechnology and Biological Sciences Research Council (BBSRC) project grant (G20234). The authors acknowledge the funding and support of the National Institutes of Health(NIH) National Eye Institute grant 1RO1EY018246, and the NIH Center for Inherited Diseases Research (CIDR) (PI: Terri Young). The BTNS authors acknowledge funding from the Australian National Health and Medical Research Council (NHMRC, grants 241944, 339462, 389927, 389875, 389891, 389892, 389938, 443036, 442915, 442981, 496739, 552485, 552498), Australian Research Council (A7960034, A79906588, A79801419, DP0212016, DP0343921); National Institutes of Health National Cancer Institute (CA88363). DLD and GWM were supported by the NHMRC Fellowships scheme. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

COMPETING INTERESTS: The authors have declared that no competing interests exist.

CITATION: Liu F, Wollstein A, Hysi PG, Ankra-Badu GA, Spector TD, et al. (2010) Digital Quantification of Human Eye Color Highlights Genetic Association of Three New Loci. PLoS Genet 6(5): e1000934. doi:10.1371/journal.pgen.1000934

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CONTACT:
Prof. Dr. Manfred Kayser
+31-10-7038093
m.kayser@erasmusmc.nl

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