LENGTH POLYMORPHISMS IN AN INTRON OF AMINOPEPTIDASE N PROVIDE A USEFUL NUCLEAR DNA MARKER FOR LITTORINA SPECIES (CAENOGASTROPODA)
Bibliographic record
Abstract
Studies of population genetic structure and hybridization among ecotypes of Littorina require both mitochondrial and nuclear markers, yet relatively few nuclear markers have been described. We used universal PCR primers for aminopeptidase N that were originally developed for the Pacific oyster, to amplify the gene in Littorina subrotundata. Three different sized PCR products (320 bp, 460 bp and 720 bp) were obtained and identified as three different proteins containing the zinc‐binding motif HEXXHXW, characteristic of aminopeptidase N. We chose the locus with the longest intron, APN54, and designed primers in the flanking exon sequence that were specific for locus APN54 for Littorina species. The Littorina‐specific primers successfully amplified only the APN54 locus in all seven species of Littorina tested and showed considerable between‐ and within‐species polymorphism in intron sequence and length. We present data from two populations of two different species, L. subrotundata and L. sitkana, that show our new nuclear marker has two or three common alleles per locus and is therefore an especially efficient population marker for small sample sizes.
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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".