Heterozygosity of the major histocompatibility complex predicts later self-reported pubertal maturation in men

DNA methylation sites in early adulthood characterised by pubertal timing and development: a twin study

BACKGROUND

Puberty is a highly heritable and variable trait, with environmental factors having a role in its eventual timing and development. Early and late pubertal onset are both associated with various diseases developing later in life, and epigenetic characterisation of pubertal timing and development could lead to important insights. Blood DNA methylation, reacting to both genotype and environment, has been associated with puberty; however, such studies are relatively scarce. We investigated peripheral blood DNA methylation profiles (using Illumina 450 K and EPIC platforms) of 1539 young adult Finnish twins associated with pubertal development scale (PDS) at ages 12 and 14 as well as pubertal age (PA).

RESULTS

Fixed effect meta-analysis of the two platforms on 347,521 CpGs in common identified 58 CpG sites associated (p < 1 × 10-5) with either PDS or PA. All four CpGs associated with PA and 45 CpGs associated with PDS were sex-specific. Thirteen CpGs had a high heritability (h2: 0.51-0.98), while one CpG site (mapped to GET4) had a high shared environmental component accounting for 68% of the overall variance in methylation at the site. Utilising twin discordance analysis, we found 6 CpG sites (5 associated with PDS and 1 with PA) that had an environmentally driven association with puberty. Furthermore, genes with PDS- or PA-associated CpGs were consistently linked to various developmental processes and diseases such as breast, prostate and ovarian cancer, while methylation quantitative trait loci of associated CpG sites were enriched in immune pathways developing during puberty.

CONCLUSIONS

By identifying puberty-associated DNA methylation sites and examining the effects of sex, environment and genetics, we shed light on the intricate interplay between environment and genetics in the context of puberty. Through our comprehensive analysis, we not only deepen the understanding of the significance of both genetic and environmental factors in the complex processes of puberty and its timing, but also gain insights into potential links with disease risks.

Polycyclic aromatic hydrocarbons are associated with later puberty in girls: A longitudinal study

The objective of this study is to explore associations between PAH exposures and puberty timing in girls. Beginning in May 2014, 734 girls age 7.2-11.8 years in Chongqing, China, were enrolled in a prospective cohort study. They were followed up every 6 months from enrollment through June 2021, at which point participants were ages 13.6-18.3 years. Metabolite concentrations of four PAHs (1-hydroxypyrene [1-OHPyr], 2-hydroxynaphthalene [2-OHNap], 2-hydroxyfluorine [2-OHFlu], and 9-hydroxyphenanthrene [9-OHPhe]) were measured in urine samples at baseline. At each follow up visit, the Tanner's Sexual Maturity Rating scale was administered. Cox proportional hazards models were used to estimate associations between four urinary PAH metabolite concentrations and four markers of puberty: menarche, breast development, pubic hair development, and axillary hair development. Geometric mean concentrations of 1-OHPyr, 2-OHNap, 2-OHFlu and 9-OHPhe in urine were 0.47 μg/L, 3.31 μg/L, 1.49 μg/L, 3.75 μg/L, respectively. There were statistically significant associations between several urinary PAH metabolite concentrations and puberty outcomes. PAH metabolite concentrations were grouped as Low (<25th percentile, referent group), Moderate (25th-75th percentile) or High (>75th). Girls with moderate levels of 1-OHPyr were at higher risk of delayed pubic hair development (hazard ratio [HR]: 0.82, 95 % confidence interval [CI]: 0.68-0.99). Delayed breast development (HR: 0.77, 95 % CI: 0.60-0.99) and pubic hair development (HR: 0.76, 95 % CI: 0.60-0.95) were associated with high 2-OHNap. High c 2-OHFlu was associated with delayed pubic hair development (HR: 0.77, 95 % CI: 0.61-0.96). Delayed breast (HR: 0.79, 95 % CI: 0.64-0.97), pubic hair (HR: 0.79, 95 % CI: 0.65-0.96) and axillary hair development (HR: 0.80, 95 % CI: 0.65-0.99) was associated with moderate 9-OHPhe. In conclusion, PAH exposure may delay puberty onset in girls.

Darwin Versus Wallace: Esthetic Evolution and Preferential Mate Choice

Dominant theorizing and research surrounding the operation of intersexual selection in evolutionary psychology tends to be guided by an adaptationist framework and aligned with models of sexual selection involving direct benefits (e.g., parental care) and indirect “good gene” and condition-dependent benefits. In this way, evolutionary psychologists more often espouse Alfred Russel Wallaces’ utilitarian viewpoint that traits become attractive because they honestly signal vigor and vitality, which gives priority to natural selection. In doing so, Darwin’s esthetic perspective originally articulated in The Descent of Man and alternative models of sexual selection (e.g., Fisherian runaway), are given less consideration. This is despite some informative reviews on the topic in evolutionary psychology. In the current conceptual analysis, we discuss the potential of Prum’s Lande-Kirkpatrick (LK) null model of sexual selection to help make sense of some of the mixed evidence regarding the links between attractive traits and purported markers of phenotypic and genetic condition. We then consider how the implications of the LK null model can help to shift theoretical assumptions and guide future work in evolutionary psychology on intersexual selection.