A single episode of sexual reproduction can produce large variation in population growth rates under dual stressors
Bibliographic record
Abstract
Sexual reproduction has been a central topic in evolutionary biology because of its many costs: why have organisms evolved sexual reproduction despite the many costs of sex? To answer the question, researchers have conducted laboratory experiments to measure population growth rates with and without sexual reproduction under a stressor. Here we show that a single episode of sexual reproduction can produce a large amount of variation in population growth rates under dual stressors by laboratory experiments of a green alga, Closterium peracerosum-strigosum-littorale complex. We observed the population dynamics of the alga under dual stressors and confirmed that high salinity and low pH decreased growth rates. By comparing parental and their hybrid F1 populations, we observed larger variations in growth rates of F1 populations (i.e., transgressive segregation) when pH was low. Interestingly, even when parental populations had negative growth rates, some F1 populations showed positive growth rates in severe environmental conditions due to the large variation in population growth. By utilizing the recently obtained genomic information of the alga, we conducted a gene ontology enrichment analysis and found that genes with copy number variations between parental strains were more frequently associated with pH stress-related terms than salt stress-related terms. Our results suggest that recombination and variation in the number of gene copies might produce large genetic variation in the F1 generation. This will be an important step toward a better understanding of evolution of sex and evolutionary rescue where rapid contemporary evolution prevents population extinction in changing environments.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".