Genomic Adaptation to Acidic Environment: Evidence from<i>Helicobacter pylori</i>
Bibliographic record
Abstract
The origin of new functions is fundamental in understanding evolution, and three processes known as adaptation, preadaptation, and exaptation have been proposed as possible evolutionary pathways leading to the origin of new functions. Here we examine the origin of an acid resistance mechanism in the mammalian gastric pathogen Helicobacter pylori, with reference to these three evolutionary pathways. The mechanism involved is that H. pylori, when exposed to the acidic environment in mammalian stomach, restricts the acute proton entry across its membrane by its increased usage of positively charged amino acids in the inner and outer membrane proteins. The results of our comparative genomic analysis between H. pylori, the two closely related species Helicobacter hepaticus and Campylobacter jejuni, and other relevant proteobacterial species are incompatible with the hypotheses invoking preadaptation or exaptation. The acid resistance mechanism most likely arose by selection favoring an increased usage of positively charged lysine in membrane proteins.
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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 | 0.001 |
| 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 | 0.002 |
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".