title: Heritability and Genome-Wide Association Studies for Hair Color in a Dutch Twin Family Based Sample.
abstract: Hair color is one of the most visible and heritable traits in humans. Here, we estimated heritability by structural equation modeling (N = 20,142), and performed a genome wide association (GWA) analysis (N = 7091) and a GCTA study (N = 3340) on hair color within a large cohort of twins, their parents and siblings from the Netherlands Twin Register (NTR). Self-reported hair color was analyzed as five binary phenotypes, namely "blond versus non-blond", "red versus non-red", "brown versus non-brown", "black versus non-black", and "light versus dark". The broad-sense heritability of hair color was estimated between 73% and 99% and the genetic component included non-additive genetic variance. Assortative mating for hair color was significant, except for red and black hair color. From GCTA analyses, at most 24.6% of the additive genetic variance in hair color was explained by 1000G well-imputed SNPs. Genome-wide association analysis for each hair color showed that SNPs in the MC1R region were significantly associated with red, brown and black hair, and also with light versus dark hair color. Five other known genes (HERC2, TPCN2, SLC24A4, IRF4, and KITLG) gave genome-wide significant hits for blond, brown and light versus dark hair color. We did not find and replicate any new loci for hair color.
authors.affiliation: Department of Biological Psychology, VU University, Amsterdam 1081 BT, The Netherlands. b.lin@vu.nl.
authors.forename: Bochao Danae
authors.initials: BD
authors.lastname: Lin
authors.affiliation: Department of Biological Psychology, VU University, Amsterdam 1081 BT, The Netherlands. h.mbarek@vu.nl.
authors.forename: Hamdi
authors.initials: H
authors.lastname: Mbarek
authors.affiliation: Department of Biological Psychology, VU University, Amsterdam 1081 BT, The Netherlands. a.h.m.willemsen@vu.nl.
authors.forename: Gonneke
authors.initials: G
authors.lastname: Willemsen
authors.affiliation: Department of Biological Psychology, VU University, Amsterdam 1081 BT, The Netherlands. c.v.dolan@vu.nl.
authors.forename: Conor V
authors.initials: CV
authors.lastname: Dolan
authors.affiliation: Department of Biological Psychology, VU University, Amsterdam 1081 BT, The Netherlands. i.o.fedko@vu.nl.
authors.forename: Iryna O
authors.initials: IO
authors.lastname: Fedko
authors.affiliation: Department of Biological Psychology, VU University, Amsterdam 1081 BT, The Netherlands. a.abdellaoui@vu.nl.
authors.forename: Abdel
authors.initials: A
authors.lastname: Abdellaoui
authors.affiliation: Department of Biological Psychology, VU University, Amsterdam 1081 BT, The Netherlands. eco.de.geus@vu.nl.
authors.forename: Eco J
authors.initials: EJ
authors.lastname: de Geus
authors.affiliation: Department of Biological Psychology, VU University, Amsterdam 1081 BT, The Netherlands. d.i.boomsma@vu.nl.
authors.forename: Dorret I
authors.initials: DI
authors.lastname: Boomsma
authors.affiliation: Department of Biological Psychology, VU University, Amsterdam 1081 BT, The Netherlands. j.j.hottenga@vu.nl.
authors.forename: Jouke-Jan
authors.initials: JJ
authors.lastname: Hottenga
keywords: GRM based heritability; Genome Wide Association Study; hair color; twin-family based heritability