In: Twin research and human genetics: the official journal of the International Society for Twin Studies (ISTS) and the Human Genetics Society of Australasia, Band 19, Heft 6, S. 595-599
We identified the genetic variants for eye color by Genome-Wide Association Study (GWAS) in a Dutch Caucasian family-based population sample and examined the genetic correlation between hair and eye color using data from unrelated participants from the Netherlands Twin Register. With the Genome-wide Complex Trait Analysis software package, we found strong genetic correlations between various combinations of hair and eye colors. The strongest positive correlations were found for blue eyes with blond hair (0.87) and brown eyes with dark hair (0.71), whereas blue eyes with dark hair and brown eyes with blond hair showed the strongest negative correlations (-0.64 and -0.94, respectively). Red hair with green/hazel eyes showed the weakest correlation (-0.14). All analyses were corrected for age and sex, and we explored the effects of correcting for principal components (PCs) that represent ancestry and describe the genetic stratification of the Netherlands. When including the first three PCs as covariates, the genetic correlations between the phenotypes disappeared. This is not unexpected since hair and eye colors strongly indicate the ancestry of an individual. This makes it difficult to separate the effects of population stratification and the true genetic effects of variants on these particular phenotypes.
The PGC was funded by National Institute of Mental Health (NIMH) Grant Nos. MH085520 (to PFS) and MH080403. Statistical analyses were carried out on the Genetic Cluster Computer (http://www.geneticcluster.org) hosted by SURFsara and financially supported by the Netherlands Scientific Organization Grant No. NWO 480-05-003 (to D. Posthuma) and the department of Psychology, Vrije Universiteit Amsterdam along with a supplement from the Dutch Brain Foundation. The Bonn/Mannheim GWAS was supported by the German Federal Ministry of Education and Research (BMBF) through the Integrated Genome Research Network Systematic Investigation of the Molecular Causes of Major Mood Disorders and Schizophrenia Grant Nos. 01GS08144 and 01GS08147, under the auspices of the National Genome Research Network plus, and through the Integrated Network Integrated Understanding of Causes and Mechanisms in Mental Disorders, under the auspices of the e:Med Programme Grant Nos. 01ZX1314A and 01ZX1314G. The Bonn/Mannheim GWAS was also supported by the German Research Foundation (DFG) Grant Nos. FOR2107, RI908/11-1, and NO246/10-1. The GenRED GWAS project was supported by NIMH R01 Grant Nos. MH061686 (to DFL), MH059542 (to W.H. Coryell), MH075131 (W.B. Lawson), MH059552 (JBP), MH059541 (W.A. Scheftner), and MH060912 (MMW). Max Planck Institute of Psychiatry MARS study was supported by the BMBF Program Molecular Diagnostics: Validation of Biomarkers for Diagnosis and Outcome in Major Depression by Grant No. 01ES0811. Genotyping was supported by the Bavarian Ministry of Commerce, and the BMBF in the framework of the National Genome Research Network by Grant Nos. NGFN2 and NGFN-Plus, FKZ 01GS0481 and 01GS08145. The Netherlands Study of Depression and Anxiety and the Netherlands Twin Register contributed to Genetic Association Information Network (GAIN)-MDD and to MDD2000. Funding for NTR/NESDA was from the following: the Netherlands Organization for Scientific Research (MagW/ZonMW Grant Nos. 904-61-090, 985-10- 002, 904-61-193, 480-04-004, 400-05-717, 912-100-20; Spinozapremie Grant No. 56-464-14192; Geestkracht program Grant No. 10-000-1002); the Center for Medical Systems Biology (NWO Genomics), Biobanking and Biomolecular Resources Research Infrastructure, Vrije Universiteit's Institutes for Health and Care Research and Neuroscience Campus Amsterdam, BIC/BioAssist/RK (Grant No. 2008.024); the European Science Foundation (Grant No. EU/QLRT-2001-01254); the European Community's Seventh Framework Program (Grant No. FP7/2007-2013); ENGAGE (Grant No. HEALTH-F4-2007-201413); and the European Science Council (Grant No. ERC 230374). Genotyping was funded in part by the GAIN of the Foundation for the US National Institutes of Health, and analysis was supported by grants from GAIN and the NIMH (Grant No. MH081802). Funding for the QIMR samples was provided by the Australian National Health and Medical Research Council (Grant Nos. 241944, 339462, 389927, 389875, 389891, 389892, 389938, 442915, 442981, 496675, 496739, 552485, 552498, 613602, 613608, 613674, 619667), the Australian Research Council (Grant Nos. FT0991360, FT0991022), the FP-5 GenomEUtwin Project (Grant No. QLG2-CT-2002-01254), and the US National Institutes of Health (Grant Nos. AA07535, AA10248, AA13320, AA13321, AA13326, AA14041, MH66206, DA12854, DA019951), and the Center for Inherited Disease Research (Baltimore, MD). RADIANT was funded by the following: a joint grant from the UK Medical Research Council and GlaxoSmithKline (Grant No. G0701420); the National Institute for Health Research Specialist Biomedical Research Centre for Mental Health at the South London and Maudsley National Health Service Foundation Trust and the Institute of Psychiatry, King's College London; the UK Medical Research Council (Grant No. G0000647), and the Marie Curie Industry-Academia Partnership and Pathways (Grant No. 286213). The GENDEP study was funded by a European Commission Framework 6 grant (EC Contract Ref.: LSHB-CT-2003-503428). Genotyping of STAR*D was supported by NIMH Grant No. MH072802 (to SPH). STAR*D was funded by NIMH Grant No. N01MH90003 to the University of Texas Southwestern Medical Center at Dallas (to A.J. Rush). The CoLaus/PsyCoLaus study was supported by research grants from GlaxoSmithKline, the Faculty of Biology and Medicine of Lausanne, and the Swiss National Science Foundation (Grant Nos. 3200B0–105993, 3200B0-118308, 33CSCO-122661, 33CS30-139468, 33CS30-148401) and two grants from GlaxoSmithKline Clinical Genetics. SHIP is part of the Community Medicine Research net of the University of Greifswald, Germany, which is funded by the Federal Ministry of Education and Research (Grant Nos. 01ZZ9603, 01ZZ0103, 01ZZ0403), the Ministry of Cultural Affairs, and the Social Ministry of the Federal State of Mecklenburg–West Pomerania. Genome-wide data have been supported by the Federal Ministry of Education and Research (Grant No. 03ZIK012) and a joint grant from Siemens Healthcare, Erlangen, Germany, and the Federal State of Mecklenburg–West Pomerania. SHIP-LEGEND is funded by the DFG (Grant No. GR 1912/5-1). The TwinGene study was supported by the Swedish Ministry for Higher Education, the Swedish Research Council (Grant No. M-2005-1112), GenomEUtwin (Grant Nos. EU/QLRT-2001-01254, QLG2-CT-2002-01254), the Swedish Foundation for Strategic Research and the US National Institutes of Health (Grant No. U01 DK066134). The collection of PRISME control subjects and genotyping of the 883 Danish control subjects was supported by grants from The Danish Strategic Research Council, The Stanley Research Foundation, and H. Lundbeck A/S. The Muenster Depression cohorts were supported by the European Union (Grant No. N Health-F2-2008-222963) and by grants from the DFG (Grant Nos. FOR 2107 and DA1151/5-1 [to UD]), Innovative Medizinische Forschung of the Medical Faculty of Mu¨nster (Grant Nos. DA120903, DA111107, and DA211012 [all to UD]). Generation Scotland is supported by a Wellcome Trust Strategic Award "Stratifying Resilience and Depression Longitudinally" (Reference No.: 104036/Z/14/Z) and core support from the Chief Scientist Office of the Scottish Government Health Directorates (Grant No. CZD/16/6) and the Scottish Funding Council (Grant No. HR03006). Supplementary material cited in this article is available online at http:// dx.doi.org/10.1016/j.biopsych.2016.05.010. ; Peer reviewed ; Publisher PDF