Among the most dramatic examples of sexual selection are the weapons used in battles between rival males over access to females. As with ornaments of female choice, the most “exaggerated” sexually selected weapons vary from male to male more widely than other body parts (hypervariability), and their growth tends to be more sensitive to nutritional state or physiological condition compared with growth of other body parts (“heightened” conditional expression). Here, we use
The Japanese rhinoceros beetle
- Award ID(s):
- 2015907
- PAR ID:
- 10522705
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- Scientific Reports
- Date Published:
- Journal Name:
- Scientific Reports
- Volume:
- 13
- Issue:
- 1
- ISSN:
- 2045-2322
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract RNA seq analysis to build on recent work exploring these mechanisms in the exaggerated weapons of beetles, by examining patterns of differential gene expression in exaggerated (head and thorax horns) and non‐exaggerated (wings, genitalia) traits in the Asian rhinoceros beetle,Trypoxylus dichotomus . Our results suggest that sexually dimorphic expression of weaponry involves large‐scale changes in gene expression, relative to other traits, while nutrition‐driven changes in gene expression in these same weapons are less pronounced. However, although fewer genes overall were differentially expressed in high‐ vs. low‐nutrition individuals, the number of differentially expressed genes varied predictably according to a trait's degree of condition dependence (head horn > thorax horn > wings > genitalia). Finally, we observed a high degree of similarity in direction of effects (vectors) for subsets of differentially expressed genes across both sexually dimorphic and nutritionally responsive growth. Our results are consistent with a common set of mechanisms governing sexual size dimorphism and condition dependence. -
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Premise Multiple transitions from insect to wind pollination are associated with polyploidy and unisexual flowers in
Thalictrum (Ranunculaceae), yet the underlying genetics remains unknown. We generated a draft genome ofThalictrum thalictroides , a representative of a clade with ancestral floral traits (diploid, hermaphrodite, and insect pollinated) and a model for functional studies. Floral transcriptomes ofT. thalictroides and of wind‐pollinated, andromonoeciousT. hernandezii are presented as a resource to facilitate candidate gene discovery in flowers with different sexual and pollination systems.Methods A draft genome of
T. thalictroides and two floral transcriptomes ofT. thalictroides andT. hernandezii were obtained from HiSeq 2000 Illumina sequencing and de novo assembly.Results The
T. thalictroides de novo draft genome assembly consisted of 44,860 contigs (N50 = 12,761 bp, 243 Mbp total length) and contained 84.5% conserved embryophyte single‐copy genes. Floral transcriptomes contained representatives of most eukaryotic core genes, and most of their genes formed orthogroups.Discussion To validate the utility of these resources, potential candidate genes were identified for the different floral morphologies using stepwise data set comparisons. Single‐copy gene analysis and simple sequence repeat markers were also generated as a resource for population‐level and phylogenetic studies.
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Abstract Background More than 3,000 species of octocorals (Cnidaria, Anthozoa) inhabit an expansive range of environments, from shallow tropical seas to the deep-ocean floor. They are important foundation species that create coral “forests,” which provide unique niches and 3-dimensional living space for other organisms. The octocoral genus Renilla inhabits sandy, continental shelves in the subtropical and tropical Atlantic and eastern Pacific Oceans. Renilla is especially interesting because it produces secondary metabolites for defense, exhibits bioluminescence, and produces a luciferase that is widely used in dual-reporter assays in molecular biology. Although several anthozoan genomes are currently available, the majority of these are hexacorals. Here, we present a de novo assembly of an azooxanthellate shallow-water octocoral, Renilla muelleri.
Findings We generated a hybrid de novo assembly using MaSuRCA v.3.2.6. The final assembly included 4,825 scaffolds and a haploid genome size of 172 megabases (Mb). A BUSCO assessment found 88% of metazoan orthologs present in the genome. An Augustus ab initio gene prediction found 23,660 genes, of which 66% (15,635) had detectable similarity to annotated genes from the starlet sea anemone, Nematostella vectensis, or to the Uniprot database. Although the R. muelleri genome may be smaller (172 Mb minimum size) than other publicly available coral genomes (256–448 Mb), the R. muelleri genome is similar to other coral genomes in terms of the number of complete metazoan BUSCOs and predicted gene models.
Conclusions The R. muelleri hybrid genome provides a novel resource for researchers to investigate the evolution of genes and gene families within Octocorallia and more widely across Anthozoa. It will be a key resource for future comparative genomics with other corals and for understanding the genomic basis of coral diversity.
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Phenotypic plasticity is thought to be an important driver of diversification and adaptation to environmental variation, yet the genomic mechanisms mediating plastic trait development and evolution remain poorly understood. The Scarabaeinae, or true dung beetles, are a species-rich clade of insects recognized for their highly diversified nutrition-responsive development including that of cephalic horns—evolutionarily novel, secondary sexual weapons that exhibit remarkable intra- and interspecific variation. Here, we investigate the evolutionary basis for horns as well as other key dung beetle traits via comparative genomic and developmental assays. We begin by presenting chromosome-level genome assemblies of three dung beetle species in the tribe Onthophagini (> 2500 extant species) including
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Abstract Understanding the origin of novel morphological traits is a long‐standing objective in evolutionary developmental biology. We explored the developmental genetic mechanisms that underpin the formation of a textbook example of evolutionary novelties, the cephalic horns of beetles. Previous work has implicated the gene regulatory networks associated with compound eye and ocellar development in horn formation and suggested that horns and compound eyes may influence each other's sizes. Therefore, we investigated the functional significance of genes central to visual system formation in the initiation, patterning, and size determination of head horns across three horned beetle species. We find that while the downregulation of canonical eye patterning genes reliably reduces or eliminates compound eye formation, it does not alter the position or shape of head horns yet does result in an increase in relative horn length. We discuss the implications of our results for our understanding of the genesis of cephalic horns in particular and evolutionary novelties in general.
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1038/s41598-023-35246-w
