ACCELERATED MOLECULAR EVOLUTION IN HALOPHILIC CRUSTACEANS
Bibliographic record
Abstract
In contrast to the stable ionic composition of the oceans, inland waters show striking diversity, possessing salt concentrations varying from I mM to 5 M. Although species diversity is highest in fresh water, some lineages have colonized hypersaline environments where they encounter elevated levels of both ultraviolet (UV) radiation and osmotic stress. This study compares rates of evolution in halophilic and freshwater taxa for two groups of microcrustaceans, anostracans and daphniids, from Australia and North America. The results establish that halophilic species show consistent rate acceleration, involving elevated levels of both insertion/deletion events and of nucleotide substitutions. The elevated pace of molecular evolution does not appear to be linked to selection or to other agents that are known to influence the supply rate of mutations, such as UV exposure, generation length, or shifts in metabolic rate. However, variance in ionic strength, which is known to have potent effects on DNA-protein interactions as well as on the structural properties of DNA and proteins, might account for the lowered fidelity of DNA replication in life from hypersaline settings. Regardless of its cause, the consistent rate acceleration in halophiles suggests that past efforts to employ sequence divergences to date events, such as the age of asexual lineages in Artemia, have resulted in serious overestimates. More generally, the results indicate that coordinated shifts in rates of molecular evolution may occur in lineages exposed to extreme environmental conditions.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.000 | 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".