The compact genome of the sponge <i>Oopsacas minuta</i> (Hexactinellida) is lacking key metazoan core genes
Bibliographic record
Abstract
ABSTRACT Background Bilaterian animals today represent 99% of animal biodiversity. Elucidating how bilaterian hallmarks emerged is a central question of animal evo-devo and evolutionary genomics. Studies of non-bilaterian genomes have suggested that the ancestral animal already possessed a diversified developmental toolkit, including some pathways required for bilaterian body plans. Comparing genomes within the early branching metazoan Porifera phylum is key to identify which changes and innovations contributed to the successful transition towards bilaterians. Results Here, we report the first whole genome comprehensive analysis of a glass sponge, Oopsacas minuta , a member of the Hexactinellida . Studying this class of sponge is evolutionary relevant because it differs from the three other Porifera classes in terms of development, tissue organization, ecology and physiology. Although O. minuta does not exhibit drastic body simplifications, its genome is among the smallest animal genomes sequenced so far, surprisingly lacking several metazoan core genes (including Wnt and several key transcription factors). Our study also provided the complete genome of the symbiotic organism dominating the associated microbial community: a new Thaumarchaeota species. Conclusions The genome of the glass sponge O. minuta differs from all other available sponge genomes by its compactness and smaller number of predicted proteins. The unexpected losses of numerous genes considered as ancestral and pivotal for metazoan morphogenetic processes most likely reflect the peculiar syncytial organization in this group. Our work further documents the importance of convergence during animal evolution, with multiple emergences of sponge skeleton, electrical signaling and multiciliated cells.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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".