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Biology subjects

Zietsch, B. P.

Publications and source records attributed to Zietsch, B. P..

3 recordsLinked to original sources

The Gender Attractiveness Gap

Writers from Darwin to Dawkins have noted that, in humans, women are considered the "beautiful sex," whereas in most species, it is the males who display more elaborate and visually striking traits. This reversal of typical sex roles is a peculiarity of the human species and has been the focus of extensive theoretical debate. Yet, it has never been systematically examined or empirically verified. Here, we present a comprehensive cross-cultural meta-analysis of same-sex and opposite-sex ratings of facial attractiveness from around the globe. Our findings confirm the existence of a robust "Gender Attractiveness Gap" (GAP), with female faces rated significantly more attractive than male faces across rater genders, cultural backgrounds, and portrayed ethnicities. Notably, the effect is more pronounced among female than male raters, suggesting gender-specific modulation. We show that approximately two-thirds of the GAP is mediated by structural facial sex-typicality. However, this mediation is asymmetric: controlling for facial dimorphism substantially reduces the attractiveness of female--but not male--faces, indicating a specific aesthetic preference for structural femininity by both male and female raters. This suggests that attractiveness judgments are driven by general aesthetic evaluation processes that extend beyond heterosexual mate choice. We also observe a general tendency for greater stringency among male raters. Overall, these findings contribute to evolutionary psychology and social perception, offering new insights into mate selection theories and underscoring the importance of accounting for gender-specific and cultural influences in attractiveness judgments.

evolutionary biology↗

Agent-Based Modelling shows that Operation of Fisher's Principle Does Not Deplete Heritability in Offspring Sex Ratio

The evolutionary basis of the ratio of male to female births has been a focus of research for over a century. Fishers principle suggests that offspring sex ratios remain roughly equal due to negative frequency-dependent balancing selection: individuals with alleles that produce the rarer sex have greater fitness, increasing these alleles frequency until the sex ratio is balanced. However, recent analysis of Swedish births since 1932 reveals that offspring sex ratio is not heritable, challenging Fishers principles application to humans. Here, we test the hypothesis that Fishers principle uniquely depletes offspring sex ratio heritability at equilibrium. We used agent-based modelling to simulate Fishers principle over 5000 generations and found that Fishers principle at equilibrium does not eliminate genetic variation. These findings, along with evidence of non-heritable offspring sex ratios in humans, suggest Fishers principle is not a suitable explanatory framework for human offspring sex ratio.

evolutionary biology↗

Genetic Consequences of Social Stratification in Great Britain

Human DNA varies across geographic regions, with most variation observed so far reflecting distant ancestry differences. Here, we investigate the geographic clustering of genetic variants that influence complex traits and disease risk in a sample of ~450,000 individuals from Great Britain. Out of 30 traits analyzed, 16 show significant geographic clustering at the genetic level after controlling for ancestry, likely reflecting recent migration driven by socio-economic status (SES). Alleles associated with educational attainment (EA) show most clustering, with EA-decreasing alleles clustering in lower SES areas such as coal mining areas. Individuals that leave coal mining areas carry more EA-increasing alleles on average than the rest of Great Britain. In addition, we leveraged the geographic clustering of complex trait variation to further disentangle regional differences in socio-economic and cultural outcomes through genome-wide association studies on publicly available regional measures, namely coal mining, religiousness, 1970/2015 general election outcomes, and Brexit referendum results.

genetics↗