scholarly journals Support for the Adaptive Decoupling Hypothesis from Whole-Transcriptome Profiles of a Hypermetamorphic and Sexually Dimorphic Insect, Neodiprion lecontei

2019 ◽  
Author(s):  
Danielle K. Herrig ◽  
Kim L. Vertacnik ◽  
Anna R. Kohrs ◽  
Catherine R. Linnen

Though seemingly bizarre, the dramatic post-embryonic transformation that occurs during metamorphosis is one of the most widespread and successful developmental strategies on the planet. The adaptive decoupling hypothesis (ADH) proposes that metamorphosis is an adaptation for optimizing expression of traits across life stages that experience opposing selection pressures. Similarly, sex-biased expression of traits is thought to evolve in response to sexually antagonistic selection. Both hypotheses predict that traits will be genetically decoupled among developmental stages and sexes, but direct comparisons between stage-specific and sex-specific decoupling are rare. Additionally, tests of the ADH have been hampered by a lack of suitable traits for among-stage comparisons and by uncertainties regarding how much decoupling is to be expected. To fill these voids, we characterize transcriptome-wide patterns of gene-expression decoupling in the hypermetamorphic and sexually dimorphic insect, Neodiprion lecontei. This species has three ecologically and morphologically distinct larval stages separated by molts, as well as a complete metamorphic transition that produces dimorphic adult males and females. Consistent with the ADH, we observe that: (1) the decoupling of gene expression becomes more pronounced as the ecological demands of developmental stages become more dissimilar and (2) gene-expression traits that mediate changing ecological interactions show stronger and more variable decoupling than expression traits that are likely to experience more uniform selection. We also find that gene-expression decoupling is more pronounced among major life stages than between the sexes. Overall, our results demonstrate that patterns of gene-expression decoupling can be predicted based on gene function and organismal ecology.

Reproduction ◽  
2014 ◽  
Vol 147 (1) ◽  
pp. 53-64 ◽  
Author(s):  
Chubin Qin ◽  
Li Xu ◽  
Yalin Yang ◽  
Suxu He ◽  
Yingying Dai ◽  
...  

To increase the knowledge of probiotic effects on zebrafish (Danio rerio), we compare the effects of two probiotic strains, Lactobacillus rhamnosus CICC 6141 (a highly adhesive strain) and Lactobacillus casei BL23 (a weakly adhesive strain), on zebrafish reproduction and their offsprings' innate level of immunity to water-borne pathogens. During probiotics treatments from 7 to 28 days, both the Lactobacillus strains, and especially L. casei BL23, significantly increased fecundity in zebrafish: higher rates of egg ovulation, fertilization, and hatching were observed. Increased densities of both small and large vitellogenic follicles, seen in specimens fed either Lactobacillus strain, demonstrated accelerated oocyte maturation. Feeding either strain of Lactobacillus upregulated gene expression of leptin, kiss2, gnrh3, fsh, lh, lhcgr, and paqr8, which were regarded to enhance fecundity and encourage oocyte maturation. Concomitantly, the gene expression of bmp15 and tgfb1 was inhibited, which code for local factors that prevent oocyte maturation. The beneficial effects of the Lactobacillus strains on fecundity diminished after feeding of the probiotics was discontinued, even for the highly adhesive gut Lactobacillus strain. Administering L. rhamnosus CICC 6141 for 28 days was found to affect the innate immunity of offspring derived from their parents, as evinced by a lower level of alkaline phosphatase activity in early larval stages. This study highlights the effects of probiotics both upon the reproductive process and upon the offsprings' immunity during early developmental stages.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Gilbert O. Silveira ◽  
Murilo S. Amaral ◽  
Helena S. Coelho ◽  
Lucas F. Maciel ◽  
Adriana S. A. Pereira ◽  
...  

AbstractReverse-transcription quantitative real-time polymerase chain reaction (RT-qPCR) is the most used, fast, and reproducible method to confirm large-scale gene expression data. The use of stable reference genes for the normalization of RT-qPCR assays is recognized worldwide. No systematic study for selecting appropriate reference genes for usage in RT-qPCR experiments comparing gene expression levels at different Schistosoma mansoni life-cycle stages has been performed. Most studies rely on genes commonly used in other organisms, such as actin, tubulin, and GAPDH. Therefore, the present study focused on identifying reference genes suitable for RT-qPCR assays across six S. mansoni developmental stages. The expression levels of 25 novel candidates that we selected based on the analysis of public RNA-Seq datasets, along with eight commonly used reference genes, were systematically tested by RT-qPCR across six developmental stages of S. mansoni (eggs, miracidia, cercariae, schistosomula, adult males and adult females). The stability of genes was evaluated with geNorm, NormFinder and RefFinder algorithms. The least stable candidate reference genes tested were actin, tubulin and GAPDH. The two most stable reference genes suitable for RT-qPCR normalization were Smp_101310 (Histone H4 transcription factor) and Smp_196510 (Ubiquitin recognition factor in ER-associated degradation protein 1). Performance of these two genes as normalizers was successfully evaluated with females maintained unpaired or paired to males in culture for 8 days, or with worm pairs exposed for 16 days to double-stranded RNAs to silence a protein-coding gene. This study provides reliable reference genes for RT-qPCR analysis using samples from six different S. mansoni life-cycle stages.


Zootaxa ◽  
2020 ◽  
Vol 4857 (1) ◽  
pp. 160-195
Author(s):  
QING-HAI FAN ◽  
DONGMEI LI ◽  
SHERLY GEORGE

In mites of the family Acaridae, usually two developmental stages, adult (males, females) and deutonymphal stage (=hypopus) are used for diagnostic descriptions. Because these taxonomically important stages live in different habitats (i.e. deutonymphs are phoretic on a hymenopteran host, while adults live inside the nest of the host), one of these can be missing or they cannot be confidently corelated with each other. Sennertionyx manicati (Acari: Acaridae) was only known from hypopus. Herein, we describe all post-embryonic stages of S. manicati based on material obtained from a nest of Anthidium manicatum in Auckland, New Zealand, and provide a key to all life stages of this species. We also conducted a phylogenetic analysis of the 18S gene and the D2/D3 region of 28S genes from field-collected specimens and GenBank data. The molecular analysis indicated the New Zealand specimen shared the identical 18S and 99.5% identity of the D2D3 region of 28S sequences with S. manicati from Italy, and clustered together in the phylogenetic trees. 


2020 ◽  
Author(s):  
Min R. Lu ◽  
Cheng-Kuo Lai ◽  
Ben-Yang Liao ◽  
Isheng Jason Tsai

AbstractNematodes are highly abundant animals with diverse habitats and lifestyles. Some are free-living while others parasitize animals or plants, and among the latter, infection abilities change across developmental stages to infect hosts and complete life cycles. Although parasitism has independently arisen multiple times over evolutionary history, common pressures of parasitism—such as adapting to the host environment, evading and subverting the host immune system, and changing environments across life cycles—have led phenotypes and developmental stages among parasites to converge. To determine the relationship between transcriptome evolution and morphological divergences among nematodes, we compared 48 transcriptomes of different developmental stages across eight nematode species. The transcriptomes were clustered broadly into embryo, larva, and adult stages, suggesting that gene expression is conserved to some extent across the entire nematode life cycle. Such patterns were partly accounted for by tissue-specific genes—such as those in oocytes and the hypodermis—being expressed at different proportions. Although nematodes typically have 3-5 larval stages, the transcriptomes for these stages were found to be highly correlated within each species, suggesting high similarity among larval stages across species. For the Caenorhabditis elegans-C. briggsae and Strongyloides stercoralis-S. venezuelensis comparisons, we found that around 50% of genes were expressed at multiple stages, whereas half of their orthologues were also expressed in multiple but different stages. Such frequent changes in expression have resulted in concerted transcriptome evolution across adjacent stages, thus generating species-specific transcriptomes over the course of nematode evolution. Our study provides a first insight into the evolution of nematode transcriptomes beyond embryonic development.


2019 ◽  
Author(s):  
AR. Issa ◽  
J. Picao-Osorio ◽  
N. Rito ◽  
M.E. Chiappe ◽  
C.R. Alonso

ABSTRACTMovement is the main output of the nervous system. It emerges during development to become a highly coordinated physiological process essential to the survival and adaptation of the organism to the environment. Similar movements can be observed in morphologically-distinct developmental stages of an organism, but it is currently unclear whether these movements have a common or diverse molecular basis. Here we explore this problem in Drosophila focusing on the roles played by the microRNA (miRNA) locus miR-iab4/8 which was previously shown to be essential for the fruit fly larva to correct its orientation if turned upside down (self-righting) (Picao-Osorio et al., 2015). Our study shows that miR-iab4 is required for normal self-righting across all three Drosophila larval stages. Unexpectedly, we also discover that this miRNA is essential for normal self-righting behaviour in the Drosophila adult, an organism with radically different morphological and neural constitution. Through the combination of gene-expression, optical imaging and quantitative behavioural approaches we provide evidence that miR-iab4 exerts its effects on adult self-righting behaviour through repression of the Hox gene Ultrabithorax (Ubx) (Morgan, 1923; Sánchez-Herrero et al., 1985) in a specific set of motor neurons that innervate the adult Drosophila leg. Our results show that this miRNA-Hox module affects the function, rather than the morphology of motor neurons and indicate that post-developmental changes in Hox gene expression can modulate behavioural outputs in the adult. Altogether our work reveals that a common miRNA-Hox genetic module can control complex movement in morphologically-distinct organisms and describes a novel post-developmental role of the Hox genes in adult neural function.


2016 ◽  
Author(s):  
Fiona C Ingleby ◽  
Claire L Webster ◽  
Tanya M Pennell ◽  
Ilona Flis ◽  
Edward H Morrow

Sexual dimorphism is predicted to be constrained by the underlying genetic architecture shared between the sexes and through ontogeny, but whole-transcriptome data for both sexes across genotypes and developmental stages are lacking. Within a quantitative genetic framework, we sequenced RNA from Drosophila melanogaster at different developmental stages to examine sex-biased gene expression and how selection acts upon it. We found evidence that gene expression is constrained by both univariate and multivariate shared genetic variation between genes, sexes and developmental stages, but may be resolved by differential splicing. These results provide a comprehensive picture of how conflict over sexual dimorphism varies through development and clarifies the conditions under which it is predicted to evolve.


2021 ◽  
Author(s):  
Jelisaveta Djordjevic ◽  
Zoé Dumas ◽  
Marc Robinson-Rechavi ◽  
Tanja Schwander ◽  
Darren James Parker

AbstractSexually dimorphic phenotypes are thought to arise primarily from sex-biased gene expression during development. Major changes in developmental strategies, such as the shift from hemimetabolous to holometabolous development, are therefore expected to have profound consequences for the dynamics of sex-biased gene expression. However, no studies have previously examined sex-biased gene expression over development in hemimetabolous insects, precluding comparisons between developmental strategies. Here we characterized sex-biased gene expression at three developmental stages in a hemimetabolous stick insect (Timema californicum): hatchlings, juveniles, and adults. As expected, the proportion of sex-biased genes gradually increased over development. Sex-biased genes identified at early developmental stages were generally consistently male- or female-biased at later stages, suggesting their importance in sexual differentiation. We then compared the dynamics of sex-biased gene expression over development in T. californicum to those of the holometabolous fly Drosophila melanogaster by reanalyzing publicly available RNA-seq data from third instar larval, pupal and adult stages. In D. melanogaster, sex-biased gene expression increases abruptly at the adult stage when morphological sexual dimorphism is manifested. This supports the prediction that sex-biased gene expression mirrors phenotypic sexual dimorphism. Our study details for the first time the dynamics of sex-biased gene expression over development in a hemimetabolous insect and suggests that these dynamics differ extensively between holometabolous and hemimetabolous species.


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