Genome assembly and methylome analysis of the white wax scale insect provides insight into sexual differentiation of metamorphosis in hexapods
Bibliographic record
Abstract
Scale insects are hemimetabolous, showing "incomplete" metamorphosis and no true pupal stage. Ericerus pela, commonly known as the white wax scale insect (hereafter, WWS), is a wax-producing insect found in Asia and Europe. WWS displays dramatic sexual dimorphism, with notably different metamorphic fates in males and females. Males develop into winged adults, while females are neotenic and maintain a nymph-like appearance, which are flightless and remain stationary. Here, we report the de novo assembly of the WWS genome with a size of 638.30 Mbp (69.68 Mbp for scaffold N50) by PacBio sequencing and Hi-C. These data allowed us to perform a robust phylogenetic analysis comprising 24,923 gene orthogroups from 16 representative insect genomes. This analysis indicated that holometabola evolved from insects with incomplete metamorphosis in the Late Carboniferous, about 50 million years earlier than previously thought. To study the distinct developmental fates of males and females, we analysed the methylome landscape in either sex. Surprisingly, WWS displayed high methylation levels (4.42% for males) when compared to other insects. We observed differential methylation patterns in males and females for genes involved in steroid and sesquiterpenoid production as well as genes acting in fatty acid metabolism pathways. We measured titre profiles for ecdysone, the principal insect steroid hormone, and juvenile hormone (a sesquiterpenoid) in both males and females, which suggested that these hormones are the primary drivers of sexually dimorphic development. Our results provide a comprehensive genomic and epigenomic resource of scale insects that provide new insights into the evolution of metamorphosis and sexual dimorphism in insects.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".