scholarly journals Developing a transcriptomic framework for testing testosterone-mediated handicap hypotheses

2019 ◽  
Author(s):  
Daniel J. Newhouse ◽  
Ben J. Vernasco
Keyword(s):  
Oxidative Stress ◽  
Selection Criteria ◽  
Rna Seq ◽  
Proximate Mechanisms ◽  
Honest Signals ◽  
Sexually Selected Traits ◽  
Evolutionarily Conserved ◽  
Transcriptomic Signature ◽  
Selected Traits ◽  
Handicap Hypothesis

ABSTRACTSexually selected traits are hypothesized to be honest signals of individual quality due to the costs associated with their maintenance, development, and/or production. Testosterone, a sex steroid associated with the development and/or production of sexually selected traits, has been proposed to enforce the honesty of sexually selected traits via its immunosuppressive effects (i.e., the Immunocompetence Handicap Hypothesis) and/or by influencing an individual’s exposure/susceptibility to oxidative stress (i.e., the Oxidation Handicap Hypothesis). Previous work testing these hypotheses has primarily focused on physiological measurements of immunity or oxidative stress, but little is known about the molecular pathways by which testosterone could influence immunity and/or oxidative stress pathways. To further understand the transcriptomic consequences of experimentally elevated testosterone in the context of handicap hypotheses, we used previously published RNA-seq data from studies that measured the transcriptome of individuals treated with either a testosterone-filled or an empty (i.e., control) implant. Two studies encompassing three species of bird and three tissue types fit our selection criteria and we reanalyzed the data using weighted gene co-expression network analysis. Our results show that testosterone-treated individuals exhibited signatures of immunosuppression and we provide some evidence to suggest that the transcriptomic signature of immunosuppression is evolutionarily conserved between the three species. While our results provide no evidence to suggest testosterone mediates handicaps via pathways associated with oxidative stress, they do support the hypothesis that testosterone enforces the honesty of sexually-selected traits by influencing an individual’s immunocompetence. Overall, this study develops a framework for testing testosterone-mediated handicap hypotheses and provides guidelines for future integrative and comparative studies focused on the proximate mechanisms mediating sexually selected traits.

scholarly journals Testosterone and oxidative stress: the oxidation handicap hypothesis

2006 ◽  
Vol 274 (1611) ◽  
pp. 819-825 ◽  
Author(s):  
Carlos Alonso-Alvarez ◽  
Sophie Bertrand ◽  
Bruno Faivre ◽  
Olivier Chastel ◽  
Gabriele Sorci
Keyword(s):  
Oxidative Stress ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Cell Resistance ◽  
Secondary Sexual Traits ◽  
Honest Signals ◽  
Mixed Support ◽  
Immunocompetence Handicap Hypothesis ◽  
Handicap Hypothesis ◽  
The Cost

Secondary sexual traits (SST) are usually thought to have evolved as honest signals of individual quality during mate choice. Honesty of SST is guaranteed by the cost of producing/maintaining them. In males, the expression of many SST is testosterone-dependent. The immunocompetence handicap hypothesis has been proposed as a possible mechanism ensuring honesty of SST on the basis that testosterone, in addition to its effect on sexual signals, also has an immunosuppressive effect. The immunocompetence handicap hypothesis has received mixed support. However, the cost of testosterone-based signalling is not limited to immunosuppression and might involve other physiological functions such as the antioxidant machinery. Here, we tested the hypothesis that testosterone depresses resistance to oxidative stress in a species with a testosterone-dependent sexual signal, the zebra finch. Male zebra finches received subcutaneous implants filled with flutamide (an anti-androgen) or testosterone, or kept empty (control). In agreement with the prediction, we found that red blood cell resistance to a free radical attack was the highest in males implanted with flutamide and the lowest in males implanted with testosterone. We also found that cell-mediated immune response was depressed in testosterone-treated birds, supporting the immunocompetence handicap hypothesis. The recent finding that red blood cell resistance to free radicals is negatively associated with mortality in this species suggests that benefits of sexual signalling might trade against the costs derived from oxidation.

scholarly journals The efficacy of sexual selection under environmental change

2018 ◽  
Author(s):  
Ivain Martinossi-Allibert ◽  
Claus Rueffler ◽  
Göran Arnqvist ◽  
David Berger
Keyword(s):  
Sexual Selection ◽  
Environmental Change ◽  
Low Cost ◽  
Empirical Studies ◽  
Fertilization Success ◽  
Honest Signals ◽  
Sexually Selected Traits ◽  
Deleterious Alleles ◽  
Fecundity Selection ◽  
Selected Traits

AbstractSexual selection can promote adaptation if sexually selected traits are reliable indicators of genetic quality. Moreover, stronger sexual selection in males, as often reported in empirical studies, may help purge deleterious alleles at a low cost to population productivity. However, to what extent this remains true when a changing environment affects sexual selection dynamics has been debated. Here, we show that even if sexually selected traits remain honest signals of male quality in new environments, the efficacy of sexual selection will often be reduced under stress. We model the strength of sex-specific selection under different levels of environmental stress in a population in which males compete with each other for fertilization success and in which females experience fecundity selection. We observe that the strength of sexual selection is reduced relative to fecundity selection, resulting in a lowered potential for selection on males to aid adaptation under environmental change.

Tests of the positive and functional allometry hypotheses for sexually selected traits in the Jamaican field cricket

2021 ◽  
pp. 104413
Author(s):  
Susan M. Bertram ◽  
Danya D. Yaremchuk ◽  
Mykell L. Reifer ◽  
Amy Villareal ◽  
Matthew J. Muzzatti ◽  
...  
Keyword(s):  
Field Cricket ◽  
Sexually Selected Traits ◽  
Selected Traits

scholarly journals Meta-Analysis of Oxidative Transcriptomes in Insects

Antioxidants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 345
Author(s):  
Hidemasa Bono
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Meta Analysis ◽  
Adherens Junction ◽  
Enrichment Analysis ◽  
Oxidative Stress Response ◽  
Insect Species ◽  
Rna Seq ◽  
Manual Curation ◽  
Analysis Workflow

Data accumulation in public databases has resulted in extensive use of meta-analysis, a statistical analysis that combines the results of multiple studies. Oxidative stress occurs when there is an imbalance between free radical activity and antioxidant activity, which can be studied in insects by transcriptome analysis. This study aimed to apply a meta-analysis approach to evaluate insect oxidative transcriptomes using publicly available data. We collected oxidative stress response-related RNA sequencing (RNA-seq) data for a wide variety of insect species, mainly from public gene expression databases, by manual curation. Only RNA-seq data of Drosophila melanogaster were found and were systematically analyzed using a newly developed RNA-seq analysis workflow for species without a reference genome sequence. The results were evaluated by two metric methods to construct a reference dataset for oxidative stress response studies. Many genes were found to be downregulated under oxidative stress and related to organ system process (GO:0003008) and adherens junction organization (GO:0034332) by gene enrichment analysis. A cross-species analysis was also performed. RNA-seq data of Caenorhabditis elegans were curated, since no RNA-seq data of insect species are currently available in public databases. This method, including the workflow developed, represents a powerful tool for deciphering conserved networks in oxidative stress response.

scholarly journals Evolution, expression and functional analysis of cultivated allotetraploid cotton DIR genes

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Zhengwen Liu ◽  
Xingfen Wang ◽  
Zhengwen Sun ◽  
Yan Zhang ◽  
Chengsheng Meng ◽  
...  
Keyword(s):  
Gene Family ◽  
Stress Responses ◽  
Rapid Evolution ◽  
Gene Clusters ◽  
Vital Role ◽  
Fiber Development ◽  
Rna Seq ◽  
Evolutionarily Conserved ◽  
Cell Wall Development ◽  
Tandem Duplications

Abstract Background Dirigent (DIR) proteins mediate regioselectivity and stereoselectivity during lignan biosynthesis and are also involved in lignin, gossypol and pterocarpan biosynthesis. This gene family plays a vital role in enhancing stress resistance and in secondary cell-wall development, but systematical understanding is lacking in cotton. Results In this study, 107 GbDIRs and 107 GhDIRs were identified in Gossypium barbadense and Gossypium hirsutum, respectively. Most of these genes have a classical gene structure without intron and encode proteins containing a signal peptide. Phylogenetic analysis showed that cotton DIR genes were classified into four distinct subfamilies (a, b/d, e, and f). Of these groups, DIR-a and DIR-e were evolutionarily conserved, and segmental and tandem duplications contributed equally to their formation. In contrast, DIR-b/d mainly expanded by recent tandem duplications, accompanying with a number of gene clusters. With the rapid evolution, DIR-b/d-III was a Gossypium-specific clade involved in atropselective synthesis of gossypol. RNA-seq data highlighted GhDIRs in response to Verticillium dahliae infection and suggested that DIR gene family could confer Verticillium wilt resistance. We also identified candidate DIR genes related to fiber development in G. barbadense and G. hirsutum and revealed their differential expression. To further determine the involvement of DIR genes in fiber development, we overexpressed a fiber length-related gene GbDIR78 in Arabidopsis and validated its function in trichomes and hypocotyls. Conclusions These findings contribute novel insights towards the evolution of DIR gene family and provide valuable information for further understanding the roles of DIR genes in cotton fiber development as well as in stress responses.

scholarly journals Sexually Selected Traits: A Fundamental Framework for Studies on Behavioral Epigenetics

ILAR Journal ◽  
2012 ◽  
Vol 53 (3-4) ◽  
pp. 253-269 ◽  
Author(s):  
E. Jasarevic ◽  
D. C. Geary ◽  
C. S. Rosenfeld
Keyword(s):  
Sexually Selected Traits ◽  
Selected Traits

scholarly journals RNA-Seq Expression Analysis of Chronic Asthmatic Mice with Bu-Shen-Yi-Qi Formula Treatment and Prediction of Regulated Gene Targets of Anti-Airway Remodeling

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Jie Cui ◽  
Zexi Lv ◽  
Fangzhou Teng ◽  
La Yi ◽  
Weifeng Tang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Gene Network ◽  
Structural Changes ◽  
Airway Remodeling ◽  
Signal Pathways ◽  
Rna Seq ◽  
Critical Nodes ◽  
Differential Expression Genes ◽  
Polymerase Chain ◽  
And Oxidative Stress

Airway remodeling is one of the typical pathological characteristics of asthma, while the structural changes of the airways in asthma are complex, which impedes the development of novel asthma targeted therapy. Our previous study had shown that Bu-Shen-Yi-Qi formula (BSYQF) could ameliorate airway remodeling in chronic asthmatic mice by modulating airway inflammation and oxidative stress in the lung. In this study, we analysed the lung transcriptome of control mice and asthmatic mouse model with/without BSYQF treatment. Using RNA-sequencing (RNA-seq) analysis, we found that 264/1746 (15.1%) of transcripts showing abnormal expression in asthmatic mice were reverted back to completely or partially normal levels by BSYQF treatment. Additionally, based on previous results, we identified 21 differential expression genes (DEGs) with fold changes (FC) > (±) 2.0 related to inflammatory, oxidative stress, mitochondria, PI3K/AKT, and MAPK signal pathways which may play important roles in the mechanism of the anti-remodeling effect of BSYQF treatment. Through inputting 21 DEGs into the IPA database to construct a gene network, we inferred Adipoq, SPP1, and TNC which were located at critical nodes in the network may be key regulators of BSYQF's anti-remodeling effect. In addition, the quantitative real-time polymerase chain reaction (qRT-PCR) result for the selected four DEGs matched those of the RNA-seq analysis. Our results provide a preliminary clue to the molecular mechanism of the anti-remodeling effect of BSYQF in asthma.

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