Genetic Epidemiology, Psychiatric Genetics, Asthma Genetics and Statistical Genetics Laboratories investigate the pattern of disease in families, particularly identical and non-identical twins, to assess the relative importance of genes and environment in a variety of important health problems.
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PMID
15169604
TITLE
A genome scan for eye color in 502 twin families: most variation is due to a QTL on chromosome 15q.
ABSTRACT
We have rated eye color on a 3-point scale (1 = blue/grey, 2 = hazel/green, 3 = brown) in 502 twin families and carried out a 5-10 cM genome scan (400-757 markers). We analyzed eye color as a threshold trait and performed multipoint sib pair linkage analysis using variance components analysis in Mx. A lod of 19.2 was found at the marker D15S1002, less than 1 cM from OCA2, which has been previously implicated in eye color variation. We estimate that 74% of variance in eye color liability is due to this QTL and a further 18% due to polygenic effects. However, a large shoulder on this peak suggests that other loci affecting eye color may be telomeric of OCA2 and inflating the QTL estimate. No other peaks reached genome-wide significance, although lods > 2 were seen on 5p and 14q and lods >1 were additionally seen on chromosomes 2, 3, 6, 7, 8, 9, 17 and 18. Most of these secondary peaks were reduced or eliminated when we repeated the scan as a two locus analysis with the 15q linkage included, although this does not necessarily exclude them as false positives. We also estimated the interaction between the 15q QTL and the other marker locus but there was only minor evidence for additive x additive epistasis. Elaborating the analysis to the full two-locus model including non-additive main effects and interactions did not strengthen the evidence for epistasis. We conclude that most variation in eye color in Europeans is due to polymorphism in OCA2 but that there may be modifiers at several other loci.
DATE PUBLISHED
2004 Apr
HISTORY
PUBSTATUS PUBSTATUSDATE
pubmed 2004/06/01 05:00
medline 2004/07/28 05:00
entrez 2004/06/01 05:00
AUTHORS
NAME COLLECTIVENAME LASTNAME FORENAME INITIALS AFFILIATION AFFILIATIONINFO
Zhu G Zhu Gu G Queensland Institute of Medical Research, Brisbane, Australia.
Evans DM Evans David M DM
Duffy DL Duffy David L DL
Montgomery GW Montgomery Grant W GW
Medland SE Medland Sarah E SE
Gillespie NA Gillespie Nathan A NA
Ewen KR Ewen Kelly R KR
Jewell M Jewell Mary M
Liew YW Liew Yew Wah YW
Hayward NK Hayward Nicholas K NK
Sturm RA Sturm Richard A RA
Trent JM Trent Jeffrey M JM
Martin NG Martin Nicholas G NG
INVESTIGATORS
JOURNAL
VOLUME: 7
ISSUE: 2
TITLE: Twin research : the official journal of the International Society for Twin Studies
ISOABBREVIATION: Twin Res
YEAR: 2004
MONTH: Apr
DAY:
MEDLINEDATE:
SEASON:
CITEDMEDIUM: Print
ISSN: 1369-0523
ISSNTYPE: Print
MEDLINE JOURNAL
MEDLINETA: Twin Res
COUNTRY: Australia
ISSNLINKING: 1369-0523
NLMUNIQUEID: 9815819
PUBLICATION TYPE
PUBLICATIONTYPE TEXT
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.
COMMENTS AND CORRECTIONS
GRANTS
GRANTID AGENCY COUNTRY
CA88363 NCI NIH HHS United States
N01-HG-65403 NHGRI NIH HHS United States
GENERAL NOTE
KEYWORDS
MESH HEADINGS
DESCRIPTORNAME QUALIFIERNAME
Chromosomes, Human, Pair 15 genetics
Eye Color genetics
Female genetics
Genetic Linkage genetics
Genetic Variation genetics
Humans genetics
Male genetics
Quantitative Trait Loci genetics
Twins genetics
SUPPLEMENTARY MESH
GENE SYMBOLS
CHEMICALS
OTHER ID's