Note: a that this adjustable are Blonde hair + blue eyes from the 1908 studies and you will Blond locks + blue/gray attention on 2004 analysis.

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, Source van Beijsterveldt, Groen-Blokhuis, Hottenga, Franic, Hudziak and you can Lamb 2013; Willemsen et al., Resource Willemsen, Vink, Abdellaoui, den Braber, van Beek and Draisma 2013) were included in this investigation according to research by the presence away from self-stated study toward natural locks and you can eye colour and also the visibility away from genotype studies on a keen Illumina 370, 660, 1M otherwise Affymetrix Perlegen-5.0, or 6.0 platform. There had been eight,063 genotyped Dutch-origins participants, clustered into the 3,407 families with investigation into attention color, site de rencontre pour célibataires sans gluten and you will six,965 genotyped someone had data towards the both hair and vision colour. On hereditary relationship data of eye color (come across Secondary topic) most of the study was analyzed. Getting bivariate hereditary analyses in the GCTA, most of the not related citizens were selected, based on an inherited relatedness matrix (GRM) cut-from 0.025 (Yang ainsi que al., Site Yang, Lee, Goddard and you may Visscher 2011). That it left step three,619 some one to your bivariate analyses, which have an inherited relatedness equal to below third otherwise fourth cousin.

, Site Willemsen, Vink, Abdellaoui, den Braber, van Beek and you will Draisma 2013). Mature people advertised their absolute hair colour in one off five selection: ‘fair/blond’, ‘hazel’, ‘red/auburn’, ‘ebony brown’, and ‘black’ and eye colour that have among around three alternatives: ‘blue/gray’, ‘green/hazel’ and you can ‘brown’. A comparable concerns into the eye color and you will tresses color were answered from the adolescent (14- so you’re able to 18-year-old) twins when they completed the Dutch Health insurance and Decisions Survey in the 2005 otherwise 2006 (van Beijsterveldt ainsi que al., Reference van Beijsterveldt, Groen-Blokhuis, Hottenga, Franic, Hudziak and you will Mutton 2013). Into analytical analyses, we combined new black, light brownish, and you can brownish hair colors so you can ‘dark’, given that simply very few people stated a black colored locks colour (Lin ainsi que al., Source Lin, Mbarek, Willemsen, Dolan, Fedko and Abdellaoui 2015). Created informed consent was obtained from the users.

Age, sex, natural hair, and you may eye colour have been obtained from Adult NTR questionnaire eight, that was accumulated during the 2004 (Willemsen mais aussi al

DNA extraction, purification, and genotype calling of the samples were performed at various points in time following the manufacturer’s protocols and genotype calling programs (Lin et al., Reference Lin, Mbarek, Willemsen, Dolan, Fedko and Abdellaoui 2015). For each platform, the individual SNPs were remapped on the build 37 (HG19), ALL 1000 Genomes Phase 1 imputation reference dataset (Auton et al., Reference Auton, Brooks, Durbin, Garrison, Kang and Korbel 2015). SNPs that failed unique mapping and SNPs with an allele frequency difference over 0.20 with the reference data were removed. SNPs with a minor allele frequency (MAF) < 0.01 were also removed, as well as SNPs that were out of Hardy–Weinberg Equilibrium (HWE) with p < 10 ?5 . The platform data were then merged into a single genotype set and the above SNP QC filters were reapplied. Samples were excluded from the data when their DNA was discordant with their expected sex or IBD status, the genotype missing rate was above 10%, the Plink F-inbreeding value was either larger than 0.10 or smaller than ?0.10, or they were an ethnic outlier based on EIGENSTRAT PCs calculated from the 1000G imputed data (Auton et al., Reference Auton, Brooks, Durbin, Garrison, Kang and Korbel 2015). Phasing of the samples and imputing cross-missing platform SNPs was done with MACH 1 (Li Abecasis, Reference Li and Abecasis 2006). The phased data were then imputed with MINIMAC to the 1000G reference. After imputation, SNPs were filtered, based on Mendelian error rate (>2%), a R 2 imputation quality value of <0.80, MAF <0.01 and a difference of more than 0.15 between the allele frequency and the reference (Howie et al., Reference Howie, Fuchsberger, Stephens, ). We tested the effect of different platforms and removed SNPs showing platform effects. This was done by defining individuals on a specific platform as cases and the others as controls. If the allelic association between the specific platform allele frequency and the other platform's allele frequency was significant (p < 10 ?5 ) SNPs were removed. This left 5,987,253 SNPs, which were all used to construct a GRM.