Analysis of area of intergradation between described subspecies of the common garter snake, Thamnophis sirtalis, in Canada
Bibliographic record
Abstract
Two area of colour pattern intergradation have been described between subspecies of the garter snake, 'Thamnophis sirtalis': one along the Manitoba/Ontario border; the other through Quebec and the New England states. Two competing hypotheses have been proposed for the origins of these areas. The first is that these areas represent regions of postglacial secondary contact between two dispersing lineages of snake. The other is that these regions represent 'in situ' differentiation of colour pattern, perhaps in response to some form of natural selection. The strict consensus tree constructed from a 364 bp portion of cytochrome ' b' sequenced from 52 snakes (24 trees, 85 steps, CI = 0.76, RI = 0.93, RC = 0.71) shows that three distinct mtDNA lineages of 'T. sirtalis ' recolonized central and eastern Canada. A "western" lineage is found in Manitoba and northeastern Ontario, an "eastern" lineage is found in northeastern and southern Ontario and in parts of Quebec and New York, and a "maritime" lineage is found in the maritime provinces and parts of the northeastern United States. The geographical regions where the various lineages meet do not correspond to the geographical position of the area of colour pattern intergradation (p < 10-17). Analysis of allozyme variation reveals considerable population substructuring (overall loci FST = 0.259) which is concordant with the distribution of mtDNA lineages. A meristic character, the number of ventral scales, also varies significantly with sex and haplotype. There is no evidence of male-biased gene flow between any of the lineages, therefore the areas of colour pattern intergradation were likely formed 'in situ'. One area of postglacial secondary contact was identified along the northern shore of Lake Superior, just east of Terrace Bay, Ontario. Neutral introgression can not be rejected as an explanation for the pattern of genetic variation observed at this area of secondary contact.
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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 | 0.002 | 0.002 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".