scholarly journals A ghost of dioecy past and the legacy of sexual dimorphism: low siring success of hermaphrodites after the breakdown of dioecy

2018 ◽  
Author(s):  
Luis Santos del Blanco ◽  
Eleri Tudor ◽  
John R. Pannell
Keyword(s):  
Sexual Dimorphism ◽  
Sexual Function ◽  
Empirical Support ◽  
Evolutionary Models ◽  
Evolutionary Transitions ◽  
Sexual Specialization ◽  
Siring Success ◽  
Mercurialis Annua

AbstractEvolutionary transitions from dioecy to hermaphroditism must overcome the inertia of sexual dimorphism because modified males or females will express the opposite sexual function for which their phenotypes have been optimized. We tested this prediction by comparing the siring success of female-derived hermaphrodites of the plant Mercurialis annua with males and hermaphrodites that present a male-like inflorescence. We found that pollen dispersed by female-derived hermaphrodites was about a third poorer at siring outcross offspring than that from hermaphrodites with male-like inflorescences, illustrating the notion that a ‘ghost of dioecy past’ compromises the fitness of derived hermaphrodites in outcrossing populations. We conclude that whereas dioecy might evolve from hermaphroditism by conferring upon individuals certain benefits of sexual specialization, reversals from dioecy to hermaphroditism must often be limited to situations in which outcrossing cannot be maintained and inbreeding is favored. Our study provides novel empirical support for evolutionary models for the breakdown of dioecy.

scholarly journals Sexual Dimorphism in the Response of Mercurialis annua to Stress

Metabolites ◽  
2016 ◽  
Vol 6 (2) ◽  
pp. 13 ◽  
Author(s):  
Ezra Orlofsky ◽  
Giorgi Kozhoridze ◽  
Lyudmila Lyubenova ◽  
Elena Ostrozhenkova ◽  
J. Winkler ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Mercurialis Annua

scholarly journals Extra base hits: widespread empirical support for instantaneous multiple-nucleotide changes

2020 ◽  
Author(s):  
Alexander G Lucaci ◽  
Sadie R Wisotsky ◽  
Stephen D. Shank ◽  
Steven Weaver ◽  
Sergei L. Kosakovsky Pond
Keyword(s):  
Evolutionary Dynamics ◽  
Synonymous Codon ◽  
Model Misspecification ◽  
Empirical Support ◽  
Simulated Data ◽  
Small Subset ◽  
Evolutionary Models ◽  
Single Nucleotide Change ◽  
Codon Substitution ◽  
Alignment Errors

AbstractDespite many attempts to introduce evolutionary models that permit substitutions that instantly alter more than one nucleotide in a codon, the prevailing wisdom remains that such changes are rare and generally negligible (or are reflective of non-biological artifacts, such as alignment errors), and codon models continue to posit that only single nucleotide change have non-zero rates. We develop and test a simple hierarchy of codon-substitution models with non-zero evolutionary rates for only one-nucleotide (1H), one- and two-nucleotide (2H), or any (3H) codon substitutions. Using 35,000 empirical alignments, we find widespread statistical support for multiple hits: 58% of alignments prefer models with 2H allowed, and 22% – with 3H allowed. Analyses of simulated data suggest that these results are not likely to be due to simple artifacts such as model misclassification or alignment errors. Further modeling revealed that synonymous codon island jumping among codons encoding serine, especially along short branches, contributes significantly to this 3H signal. While serine codons were prominently involved in multiple-hit substitutions, there were other common exchanges contributing to better model fit. It appears that a small subset of sites in most alignments have unusual evolutionary dynamics not well explained by existing model formalisms, and that commonly estimated quantities, such as dN/dS ratios may be biased by model misspecification. Our findings highlight the need for continued evaluation of assumptions underlying workhorse evolutionary models and subsequent evolutionary inference techniques. We provide a software implementation for evolutionary biologists to assess the potential impact of extra base hits in their data in the HyPhy package.

scholarly journals Sexual dimorphism and rapid turnover in gene expression in pre-reproductive seedlings of a dioecious herb

2018 ◽  
Vol 123 (7) ◽  
pp. 1119-1131 ◽  
Author(s):  
Guillaume G Cossard ◽  
Melissa A Toups ◽  
John R Pannell
Keyword(s):  
Gene Expression ◽  
Sexual Dimorphism ◽  
Rapid Evolution ◽  
Dioecious Plants ◽  
Below Ground ◽  
Annual Herb ◽  
Differential Gene ◽  
Angiosperm Species ◽  
Differential Costs ◽  
Mercurialis Annua

Abstract Background and Aims Sexual dimorphism in morphology, physiology or life history traits is common in dioecious plants at reproductive maturity, but it is typically inconspicuous or absent in juveniles. Although plants of different sexes probably begin to diverge in gene expression both before their reproduction commences and before dimorphism becomes readily apparent, to our knowledge transcriptome-wide differential gene expression has yet to be demonstrated for any angiosperm species. Methods The present study documents differences in gene expression in both above- and below-ground tissues of early pre-reproductive individuals of the wind-pollinated dioecious annual herb, Mercurialis annua, which otherwise shows clear sexual dimorphism only at the adult stage. Key Results Whereas males and females differed in their gene expression at the first leaf stage, sex-biased gene expression peaked just prior to, and after, flowering, as might be expected if sexual dimorphism is partly a response to differential costs of reproduction. Sex-biased genes were over-represented among putative sex-linked genes in M. annua but showed no evidence for more rapid evolution than unbiased genes. Conclusions Sex-biased gene expression in M. annua occurs as early as the first whorl of leaves is produced, is highly dynamic during plant development and varies substantially between vegetative tissues

scholarly journals Visual Attention and Sexual Function in Women

2021 ◽  
Author(s):  
Sonia Milani ◽  
Samantha J. Dawson ◽  
Julia Velten
Keyword(s):  
Sexual Dysfunction ◽  
Visual Attention ◽  
Sexual Function ◽  
Sexual Arousal ◽  
Empirical Support ◽  
Theoretical Models ◽  
Sexual Response ◽  
Future Research ◽  
Attentional Processing ◽  
Sexual Stimuli

Abstract Purpose of Review Theoretical models situate attention as integral to the onset and regulation of sexual response and propose that problems with sexual response and subsequent sexual dysfunction result from insufficient attentional processing of sexual stimuli. The goal of this paper is to review literature examining the link between attentional processing of sexual stimuli and sexual function in women. Specifically, we sought to understand whether women with and without sexual dysfunction differ in their visual attention to sexual stimuli and examined the link with sexual response, which would support attention as a mechanism underlying sexual dysfunction. Recent Findings Across women with and without sexual concerns, sexual stimuli are preferentially attended to relative to nonsexual stimuli, suggesting that sexual stimuli are more salient than nonsexual stimuli. Differences between women with and without sexual dysfunction emerge when examining visual attention toward the most salient features of sexual stimuli (e.g., genital regions depicting sexual activity). Consistent with theoretical models, visual attention and sexual response are related, such that increasing attention to sexual cues facilitates sexual arousal, whereas reduced attention to sexual stimuli appears to suppress sexual arousal, which may contribute to sexual difficulties in women. Summary Taken together, the research supports the role of visual attention in sexual response and sexual function. These findings provide empirical support for interventions that target attentional processing of sexual stimuli. Future research is required to further delineate the specific attentional mechanisms involved in sexual response and investigate whether these are modifiable. This knowledge may be beneficial for developing novel psychological interventions targeting attentional processes in the treatment of sexual dysfunctions.

scholarly journals Sexual selection on male vocal fundamental frequency in humans and other anthropoids

2016 ◽  
Vol 283 (1829) ◽  
pp. 20152830 ◽  
Author(s):  
David A. Puts ◽  
Alexander K. Hill ◽  
Drew H. Bailey ◽  
Robert S. Walker ◽  
Drew Rendall ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Immune Function ◽  
Fundamental Frequency ◽  
Low Frequency ◽  
Evolutionary Transitions ◽  
Mating Competition ◽  
Males And Females ◽  
Low Cortisol

In many primates, including humans, the vocalizations of males and females differ dramatically, with male vocalizations and vocal anatomy often seeming to exaggerate apparent body size. These traits may be favoured by sexual selection because low-frequency male vocalizations intimidate rivals and/or attract females, but this hypothesis has not been systematically tested across primates, nor is it clear why competitors and potential mates should attend to vocalization frequencies. Here we show across anthropoids that sexual dimorphism in fundamental frequency ( F 0 ) increased during evolutionary transitions towards polygyny, and decreased during transitions towards monogamy. Surprisingly, humans exhibit greater F 0 sexual dimorphism than any other ape. We also show that low- F 0 vocalizations predict perceptions of men's dominance and attractiveness, and predict hormone profiles (low cortisol and high testosterone) related to immune function. These results suggest that low male F 0 signals condition to competitors and mates, and evolved in male anthropoids in response to the intensity of mating competition.

scholarly journals Is there any Relationship between Sexual Attraction and Gender Typology?

2006 ◽  
Vol 9 (1) ◽  
pp. 3-9 ◽  
Author(s):  
Juan Fernández ◽  
María Ángeles Quiroga ◽  
Isabel Del Olmo
Keyword(s):  
Sexual Dimorphism ◽  
Sexual Attraction ◽  
Sex Role ◽  
Empirical Support ◽  
Close Relation ◽  
Assessment Instruments ◽  
Sex And Gender ◽  
Relative Independence ◽  
And Gender ◽  
The One

People can be classified as attracted to both sexes, to men, to women, or to neither sex, and also as instrumental-expressive, instrumental, expressive, or non-instrumental-expressive. The two hypotheses tested herein are, on the one hand, the relative independence between these two typologies and, on the other, the close relation between sexual dimorphism and sexual attraction, in contrast to the relative independence between sexual dimorphism and the instrumental and expressive domains. A total of 503 university students (284 women and 219 men) completed two assessment instruments: The Sexual Attraction Questionnaire (SAQ) and the Bem Sex Role Inventory (BSRI, 12 items). Analysis of contingency tables was performed. The results provide empirical support for the hypothesis of independence of the two typologies, solid support for the relation between sexual dimorphism and sexual attraction, and clear support for the independence between the gender domains and sexual dimorphism. The implications of these data for the different outlooks concerning the relations between sex and gender are established.

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