The authors carried out a large-scale genome-wide meta-analysis across 51 studies including several ENGAGE cohorts, to assess the potential differences between men and women in the frequency of common variants. The study material comprised overall 114,863 individuals (61,094 women and 53,769 men) of European ancestry. The rationale behind the comparison was based on the fact that the male-to-female sex ratio at birth is constant across world with an average of 1.06 (106 male to 100 female live births) for populations of European descent. Numerous biological and environmental factors are likely to be responsible for this ratio distortion, including incompatibility between autosomal and sex chromosome variants leading to differential survival of male and female embryos.
The aim of the present study was to test if also genetic factors are implicated in this phenomenon. No genome-wide significant allele frequency differences were found at common loci between men and women indicating that sex-specific selection against particular genetic variants is not a plausible explanation for the observed male-to-female sex ratio at birth. These findings were further supported by the theoretical forward-time simulations. The absence of sex-specific differences is useful in guiding genetic association study design, for example when using mixed controls for sex-biased traits (e.g. prostate cancer in men or anorexia nervosa in women).
Genome-wide meta-analysis of common variant differences between men and women
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