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Estrogen receptor 1 promoter polymorphism and digit ratio in men

Authors

  • Kathryn L. Vaillancourt,

    1. Department of Psychology, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
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  • Natalie L. Dinsdale,

    1. Department of Psychology, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
    2. Current Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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  • Peter L. Hurd

    Corresponding author
    1. Department of Psychology, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
    2. Centre for Neuroscience, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
    • Department of Psychology, University of Alberta, Edmonton T6G 2E9 AB, Canada
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Abstract

Objectives:

The 2D:4D digit ratio, the relative lengths of the index and ring fingers in humans, is a widely used proxy measure for prenatal testosterone exposure. Varying distributions of androgen and estrogen receptors on the second and fourth digits, both of which regulate digit development, appears to be the basis for this effect. Polymorphism in a tandem repeat in the gene coding for the estrogen receptor α (ESR1) in zebra finches (Taeniopygia guttata) not only explains a significant amount of variation in digit ratio but also seems to explain the significant correlation between digit ratio and sexual behavior in these birds. Here, we investigate the effect of TA polymorphism in ESR1 on 2D:4D and aggressive behavior in men.

Methods:

We genotyped ESR1 polymorphism in samples collected for a previous study in which we had demonstrated an association between androgen receptor polymorphism and aggression, but not 2D:4D.

Results:

We found a significant effect of ESR1 TA repeat number on left hand 2D:4D ratio. More TA repeats were associated with higher, more feminized, digit ratios. We found no effect on right hand 2D:4D. We also found an effect of ESR1 polymorphism on aggressive behavior. Greater heterozygosity in TA(n) was associated with lower physical aggression.

Conclusions:

Our results suggest that a significant amount of left hand 2D:4D variation and aggressive behavior is due to this variation in ESR1, and that some of the correlation between digit ratio and social behavior is due to pleiotropic effects of ESR1 variation on the two traits. Am. J. Hum. Biol., 2012. © 2012 Wiley Periodicals, Inc.

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