Sexual dimorphism in a dioecious population of the wind-pollinated herb Mercurialis annua: the interactive effects of resource availability and competition

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

Download Full-text

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

10.1101/430041 ◽

2018 ◽

Cited By ~ 1

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.

Download Full-text

Sex-Specific Dependence of Linear and Nonlinear Postural Control Metrics on Anthropometrics During Clinical Balance Tests in Healthy Young Adults

Journal of Sport Rehabilitation ◽

10.1123/jsr.2018-0197 ◽

2020 ◽

Vol 29 (4) ◽

pp. 405-412

Author(s):

Stephen M. Glass ◽

Brian L. Cone ◽

Christopher K. Rhea ◽

Donna M. Duffy ◽

Scott E. Ross

Keyword(s):

Sexual Dimorphism ◽

Postural Control ◽

Center Of Pressure ◽

Force Plate ◽

Interactive Effects ◽

Fluctuation Analysis ◽

Scaling Exponent ◽

Cross Sectional ◽

Linear And Nonlinear ◽

Positive Effect

Context: Previous work suggests that balance behavior is a sex-dependent, complex process that can be characterized by linear and nonlinear metrics. Although a certain degree of center of pressure variability may be expected based on sexual dimorphism, there is evidence to suggest that these effects are obscured by potential interactions between sex and anthropometric factors. To date, no study has accounted for such interactive effects using both linear and nonlinear measures. Objective: This investigation sought to analyze interactive models featuring sex, height, and weight as predictors of linear and nonlinear aspects of postural control. Design: Cross-sectional study. Setting: Controlled laboratory. Participants: A total of 26 males (23.80 [3.44] y, 177.87 [6.44] cm, 81.70 [10.80] kg) and 28 females (21.14 [2.03] y, 169.57 [8.80] cm, 64.48 [8.86] kg) were sampled from a healthy university population. Main Outcome Measures: Linear (range [RNG], velocity [VEL], and SD) and nonlinear (detrended fluctuation analysis scaling exponent, multivariate multiscale sample entropy [MMSECI]) summary metrics of center of pressure time series. Procedure: Participants stood on a force plate for 20 seconds in 3 conditions: double (D), single (S), and tandem (T) stance. Data for each stance condition were analyzed using regression models with interaction terms for sex × height and sex × weight. In D, weight had a positive, significant main effect on VELy, MMSECId, and MMSECIv. In men, height was observed to have a positive effect on SDy (S), RNGy (S), and RNGx (T) and a negative effect on MMSECIv (T). In women, weight was observed to have a positive effect on SDy and VELx (both T). Conclusions: Our findings suggest that men and women differ with respect to certain linear and nonlinear aspects of balance behavior, and that these differences may reflect sex-specific behavioral patterns in addition to effects related to sexual dimorphism.

Download Full-text

Interactive effects of competition and social environment on the expression of sexual dimorphism

Journal of Evolutionary Biology ◽

10.1111/jeb.12381 ◽

2014 ◽

Vol 27 (6) ◽

pp. 1069-1077 ◽

Cited By ~ 7

Author(s):

S. P. De Lisle ◽

L. Rowe

Keyword(s):

Sexual Dimorphism ◽

Social Environment ◽

Interactive Effects

Download Full-text

Epigenetics of floral homeotic genes in relation to sexual dimorphism in the dioecious plant Mercurialis annua

10.1101/481481 ◽

2018 ◽

Author(s):

Janardan Khadka ◽

Narendra Singh Yadav ◽

Micha Guy ◽

Gideon Grafi ◽

Avi Golan-Goldhirsh

Keyword(s):

Sexual Dimorphism ◽

Specific Factor ◽

Homeotic Genes ◽

Dioecious Plant ◽

Floral Homeotic Genes ◽

Class B ◽

Gender Specific ◽

Female Flowers ◽

Mercurialis Annua ◽

Floral Homeotic

AbstractIn plants, dioecy characterizes species carrying male and female flowers on separate plants and occurs in about 6% of angiosperms. To date, the molecular mechanism(s) underlying sexual dimorphism is essentially unknown. The ability of gender-reversal by hormone application suggests that epigenetics might play an important role in sexual dimorphism. Proteome analysis of nuclei derived from flower buds of females, males and feminized males of the dioecious plant Mercurialis annua revealed differentially expressed proteins related to nucleic acid binding proteins, hydrolases and transcription factors, including floral homeotic genes. Further analysis showed that class B genes are mainly expressed in male flowers, while class D genes, as well as SUPERMAN-like genes, were mainly expressed in female flowers. Cytokinin-induced feminization of male plants was associated with down-regulation of male-specific genes concomitantly with up-regulation of female-specific genes. No correlation could be found between the expression of class B and D genes and their DNA methylation or chromatin conformation. Thus, our results ruled out epigenetic control over floral identity genes as the major determinants regulating sexual dimorphisms. Rather, determination of sex in M. annua might be controlled upstream of floral identity genes by a gender-specific factor that affects hormonal homeostasis.HighlightsSex determination in Mercurialis annua is not related to epigenetics of floral homeotic genes but appears to be modulated by an unknown gender-specific regulator(s) that affects hormonal homeostasis.

Download Full-text