The genetic architecture of sexual dimorphism: the potential roles of genomic imprinting and condition-dependence

Secondary sexual traits tend to be sexually dimorphic, and theory predicts that such traits should also be condition-dependent in a sex-specific manner. We investigate these phenomena in a field study of the small Indian mongoose (Herpestes auropunctatus (Hodgson, 1836); formerly Herpestes javanicus (É. Geoffroy Saint-Hillaire, 1818)), in the first attempt at understanding secondary sexual traits and sexual selection in this species. Small Indian mongooses are solitary and nonterritorial, and they likely depend on chemical (scent) rather than visual or acoustic signals for communication. Additionally, they possess a fleshy projection around their anus, the anal pad, thought to aid in scent-marking. Our results revealed strong male-biased sexual dimorphism in mass, skull and body lengths, canine diameters, and anal pad area. After controlling for the influence of body length, males were 31% heavier and possessed anal pads that were 68% larger than females’. Additionally, anal pad size was positively related to body size in males but not in females and was condition-dependent in males but not in females. Taken together, our findings provide indirect evidence that the anal pad might have evolved, at least in part, via sexual selection.

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SEXUAL DIMORPHISM IN THE QUANTITATIVE-GENETIC ARCHITECTURE OF FLORAL, LEAF, AND ALLOCATION TRAITS IN SILENE LATIFOLIA

Evolution ◽

10.1111/j.1558-5646.2007.00004.x ◽

2007 ◽

Vol 61 (1) ◽

pp. 42-57 ◽

Cited By ~ 61

Author(s):

Janet C. Steven ◽

Lynda F. Delph ◽

Edmund D. Brodie

Keyword(s):

Sexual Dimorphism ◽

Genetic Architecture ◽

Silene Latifolia ◽

Quantitative Genetic

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SEXUAL SELECTION, GENETIC ARCHITECTURE, AND THE CONDITION DEPENDENCE OF BODY SHAPE IN THE SEXUALLY DIMORPHIC FLY PROCHYLIZA XANTHOSTOMA (PIOPHILIDAE)

Evolution ◽

10.1111/j.0014-3820.2005.tb00901.x ◽

2005 ◽

Vol 59 (1) ◽

pp. 138-151 ◽

Cited By ~ 91

Author(s):

Russell Bonduriansky ◽

Locke Rowe

Keyword(s):

Sexual Selection ◽

Genetic Architecture ◽

Body Shape ◽

Condition Dependence ◽

Sexually Dimorphic

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Sexual differences in genetic architecture in UK Biobank

10.1101/2020.07.20.211813 ◽

2020 ◽

Author(s):

Elena Bernabeu ◽

Oriol Canela-Xandri ◽

Konrad Rawlik ◽

Andrea Talenti ◽

James Prendergast ◽

...

Keyword(s):

Sexual Dimorphism ◽

Complex Traits ◽

Genetic Architecture ◽

Molecular Mechanisms ◽

Association Studies ◽

Mammalian Species ◽

Genetic Correlations ◽

European Ancestry ◽

Genome Wide Association Studies ◽

Uk Biobank

ABSTRACTSex is arguably the most important differentiating characteristic in most mammalian species, separating populations into different groups, with varying behaviors, morphologies, and physiologies based on their complement of sex chromosomes. In humans, despite males and females sharing nearly identical genomes, there are differences between the sexes in complex traits and in the risk of a wide array of diseases. Gene by sex interactions (GxS) are thought to account for some of this sexual dimorphism. However, the extent and basis of these interactions are poorly understood.Here we provide insights into both the scope and mechanism of GxS across the genome of circa 450,000 individuals of European ancestry and 530 complex traits in the UK Biobank. We found small yet widespread differences in genetic architecture across traits through the calculation of sex-specific heritability, genetic correlations, and sex-stratified genome-wide association studies (GWAS). We also found that, in some cases, sex-agnostic GWAS efforts might be missing loci of interest, and looked into possible improvements in the prediction of high-level phenotypes. Finally, we studied the potential functional role of the dimorphism observed through sex-biased eQTL and gene-level analyses.This study marks a broad examination of the genetics of sexual dimorphism. Our findings parallel previous reports, suggesting the presence of sexual genetic heterogeneity across complex traits of generally modest magnitude. Our results suggest the need to consider sex-stratified analyses for future studies in order to shed light into possible sex-specific molecular mechanisms.

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Sex differences in the genetic architecture of obsessive-compulsive disorder

10.1101/219170 ◽

2017 ◽

Cited By ~ 2

Author(s):

Ekaterina A. Khramtsova ◽

Raphael Heldman ◽

Eske M. Derks ◽

Dongmei Yu ◽

Lea K. Davis ◽

...

Keyword(s):

Sexual Dimorphism ◽

Obsessive Compulsive Disorder ◽

Sex Difference ◽

Genetic Architecture ◽

Sexually Dimorphic ◽

Obsessive Compulsive ◽

Compulsive Disorder ◽

Regulatory Variants ◽

Specific Risk ◽

Genome Wide

AbstractObsessive-compulsive disorder (OCD), a highly heritable complex phenotype, demonstrates sexual dimorphism in age of onset and clinical presentation, suggesting a possible sex difference in underlying genetic architecture. We present the first genome-wide characterization of the sex-specific genetic architecture of OCD, utilizing the largest set of OCD cases and controls available from the Psychiatric Genomics Consortium. We assessed evidence for several mechanisms that may contribute to sexual-dimorphism including a sexually dimorphic liability threshold, the presence of individual sex-specific risk variants on the autosomes and the X chromosome, genetic and phenotypic heterogeneity, and sex-specific pleiotropic effects. We observed a strong genetic correlation between male and female OCD and no evidence for a sexually dimorphic liability threshold model. While we did not detect any sex-specific genome-wide associations, we observed that the SNPs with sexually dimorphic effects showed an enrichment of regulatory variants influencing expression of genes in immune tissues. Furthermore, top sex-specific genome-wide associations were enriched for regulatory variants in different tissues, suggesting evidence for potential sex difference in the biology underlying risk for OCD. These findings suggest that future studies with larger sample sizes hold great promise for the identification of sex-specific risk factors for OCD, significantly advancing our understanding of the differences in the genetic basis of sexually dimorphic neuropsychiatric traits.

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