Familial digit ratio (2D:4D) associations in a general population sample from Wales
Early Human Development
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Richards, G., Bellin, W., & Davies, W. (2017). Familial digit ratio (2D:4D) associations in a general population sample from Wales. Early Human Development, 112 14-19. https://doi.org/10.1016/j.earlhumdev.2017.06.006
Background The relative length of the second and fourth fingers (2D:4D) may be a sex-linked correlate of prenatal androgen exposure. However, the nature of the sex-linkage is controversial, with evidence for both X- and Y-linkage of the 2D:4D phenotype. Aims To examine transgenerational effects relating to sex-linkage. In addition, assortative mating on 2D:4D was considered, as well as associations between 2D:4D and age and sex. Study design A family study was conducted. Parents and offspring completed a demographic questionnaire, and digit ratios were calculated from photocopies of participants' hands. Subjects We recruited and phenotyped 585 individuals attending a cultural festival in Wales. 2D:4D information was available for 47 mother-son dyads, 70 mother-daughter dyads, 31 father-son dyads and 30 father-daughter dyads. Outcome measures Correlations between 2D:4D of parents and children, as well as between mothers and fathers were conducted. 2D:4D was also examined in relation to age and sex. Results and conclusions There was a sex difference in 2D:4D (males < females). Within the dyads, there was a significant positive correlation between mother and daughter 2D:4D, but no significant correlation between mother and son ratios, nor between father and offspring ratios. The overall pattern of correlations (with em- phasis on father-son dyads) was not supportive of Y-linkage. There was a positive correlation between 2D:4D and age in children, and a negative correlation between 2D:4D and age in adults, and no evidence of assortative mating. Our data are consistent with the notion of 2D:4D as a sexually-dimorphic, mildly age-sensitive, and transgenerationally-transmitted trait that is more likely to be X- than Y-linked.
2D:4D, assortative mating, digit ratio, prenatal testosterone, sex hormones, sex linkage, transgenerational effects
This work was supported by a Student Research Grant from the European Human Behaviour and Evolution Association (EHBEA), which was awarded to GR. The work was partially undertaken within the Medical Research Council UK Centre for Neuropsychiatric Genetics and Genomics (MR/L010305/1). The funders played no role in study de- sign, data collection, analysis and interpretation, writing of the manu- script, or the decision to submit the article for publication.
External DOI: https://doi.org/10.1016/j.earlhumdev.2017.06.006
This record's URL: https://www.repository.cam.ac.uk/handle/1810/266184