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Results for “Sex-dimorphism”

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PubMedDate not supplied

Sex-dimorphic behaviour development in the human: prenatal hormone administration and postnatal socialization.

An interdisciplinary integrative approach must be utilized in the study of psychosexual differentiation. The approach must capitalize on data derived from non-human models, from experiments of nature, and from experiments of nurture. Studies from non-human primates strongly suggest the influence of prenatal sex hormone levels on postnatal sexually dimorphic behaviours. Starting from this basis we have studied sixty young adult men whose mothers received, during pregnancy, diethylstilboestrol, diethylstilboestrol and natural progesterone, natural progesterone, or synthetic progesterone. They have been compared with matched controls not exposed in utero to exogenous hormones. Studies of socialization patterns must document the differential developmental experiences, if any, of children with atypical and typical sex-typed behaviours. To this end, we are studying 60 boys whose behaviour before puberty was decidedly feminine, and their parents, and contrasting them with masculine boys and their parents. We are also studying 50 girls whose behaviour before puberty was 'masculine', and contrasting them with 'feminine' girls. Additionally, we are studying the sexually dimorphic behaviour of children of sexually atypical parents. The parents have either undergone sex-change surgery (male-to-female or female-to-male) or are homosexual. Data from the three studies are presented. A call is made to researchers working with non-human primates to test and extend these findings.

Child↗
PubMedDate not supplied

Psychosexual development: an examination of the role of prenatal hormones.

Naturally occurring endocrine syndromes and the offspring from steroid-treated pregnancies are the major sources of evidence for a role of prenatal hormones in psychosexual development in man. Effects of prenatal androgens have been established for the sex-dimorphic behaviour clusters of energy expenditure (increased), parenting rehearsal (decreased), peer associations (shifted to male), and grooming-related behaviour (decreased); most of the information was obtained on the syndrome of congenital adrenal hyperplasia and in progestin-induced female hermaphroditism. Studies of children and adults exposed prenatally to exogenous oestrogens and/or progestagens suggest slight demasculinizing effects but cannot yet be considered conclusive. Gender identity is largely dependent on the sex of rearing; a direct role of prenatal hormones in its formation has not been shown. The evidence for the role of prenatal hormones in the development of sexual orientation is inconclusive.

Female↗
PubMed2026

Joint Effects of Long-Term Obesity and Genetic Susceptibility on Sex-Specific Brain Aging.

OBJECTIVE: This study aimed to examine the associations of longitudinal obesity trajectories and polygenic risk with sex-specific brain aging. METHODS: We analyzed 35,092 UK Biobank participants (16,484 males and 18,608 females). Sex-specific XGBoost models estimated multimodal brain age. We derived 16-year longitudinal obesity trajectories from repeatedly collected anthropometric measurements. Polygenic risk scores were constructed based on 55 independent genetic loci. Multivariable logistic regression examined associations of obesity trajectories and genetic risk with brain age acceleration. RESULTS: A total of 8198 (49.73%) males and 9089 (48.84%) females had accelerated brain aging. High genetic risk significantly increased brain age acceleration odds (males: OR = 1.39; females: OR = 1.34). Crucially, the high-stable obesity trajectory exerted a stronger effect in males (OR = 1.90, 95% CI: 1.64-2.21) than in females (OR = 1.25, 95% CI: 1.12-1.40), with the joint presence of high genetic risk and high-stable obesity amplifying risk to an OR of 2.78 in males and 1.57 in females. Conversely, shifting from obesity to non-obesity reduced risk by 30% in males and 18% in females. CONCLUSIONS: These findings underscore long-term obesity as a critical, sex-dimorphic driver of accelerated brain aging, and midlife weight management offers robust neuroprotection even in genetically susceptible individuals.

brain aging↗
PubMed2024

The role of mitochondria in sex- and age-specific gene expression in a species without sex chromosomes.

Mitochondria perform an array of functions, many of which involve interactions with gene products encoded by the nucleus. These mitochondrial functions, particularly those involving energy production, can be expected to differ between sexes and across ages. Here, we measured mitochondrial effects on sex- and age-specific gene expression in parental and reciprocal F1 hybrids between allopatric populations of Tigriopus californicus with over 20% mitochondrial DNA divergence. Because the species lacks sex chromosomes, sex-biased mitochondrial effects are not confounded by the effects of sex chromosomes. Results revealed pervasive sex differences in mitochondrial effects, including effects on energetics and aging involving nuclear interactions throughout the genome. Using single-individual RNA sequencing, sex differences were found to explain more than 80% of the variance in gene expression. Males had higher expression of mitochondrial genes and mitochondrially targeted proteins (MTPs) involved in oxidative phosphorylation (OXPHOS), while females had elevated expression of non-OXPHOS MTPs, indicating strongly sex-dimorphic energy metabolism at the whole organism level. Comparison of reciprocal F1 hybrids allowed insights into the nature of mito-nuclear interactions, showing both mitochondrial effects on nuclear expression, and nuclear effects on mitochondrial expression. While based on a small set of crosses, sex-specific increases in mitochondrial expression with age were associated with longer life. Network analyses identified nuclear components of strong mito-nuclear interactions and found them to be sexually dimorphic. These results highlight the profound impact of mitochondria and mito-nuclear interactions on sex- and age-specific gene expression.

Animals↗
PubMed2026

An immune-associated mitochondrial DNA variant with sex differences reveals a putative novel microprotein called MASL.

The use of mitochondrial wide association studies (MiWAS) to link mitochondrial DNA variants (mtSNPs) to phenotypes of interest has uncovered important connections between mitochondrial genes and human health. The recent introduction of a re-annotated mitochondrial genome that accounts for small open reading frames (sORFs) with protein coding potential suggests the existence of mitochondrial-derived microproteins, many of which remain uncharacterized. Thus, considering the re-annotated mitochondrial genome when conducting genomic analyses such as MiWAS facilitates the mapping of mtSNPs back to microprotein-encoding sORFs and uncovers interactions between mitochondrial microproteins and biological systems. Here, we employ MiWAS of venous blood samples from the Health and Retirement Study (HRS) and identify a mtSNP associated with sex-specific changes to immune composition. After accounting for re-annotation, we map the identified mtSNP back to a sORF that encodes a novel microprotein, termed MASL (Mitochondrial Associated Small d-Loop peptide). Complementary phenome-wide association studies (PheWAS) in HRS and and UK Biobank confirm interactions between this mtSNP and immune phenotypes of interest, and our targeted RNA-Seq method (mitoSNP-seq) elucidates sex-differences in gene expression and functional pathways potentially altered by this mtSNP that may be relevant to the associated microprotein. Early characterization of the MASL microprotein shows sex-differences in circulating MASL levels in human plasma, and sex-specific interactions when comparing male and female mice treated with synthesized MASL. Together, the results of this study not only contribute to our understanding of mitochondrial dynamics in immunity, but also provide early characterization of a novel mitochondrial-derived microprotein with sex-specific modulatory effects.

Genomics↗