GENETIC ANALYSIS OF DISTINCT CLADES OF PLETHODON CINEREUS AT A SECONDARY CONTACT ZONE IN NORTHEAST OHIO
Bibliographic record
Abstract
Contact zones between species, subspecies, or incipient lineages offer important insights into the processes that maintain reproductive isolation. Plethodon cinereus, a highly abundant and wide-ranging terrestrial salamander found in the northeast United States and southeast Canada, provides an excellent model system for studying secondary contact zones. Using mtDNA, six distinct clades have been identified across the range of P. cinereus. Populations of two such clades, the Ohio (OH) clade, which dispersed through central Ohio following receding glaciers of the last glacial maximum, and the Pennsylvania (PA) clade, which dispersed through Pennsylvania and then west through northern Ohio, can be found approximately 9.4 km apart in Lorain County, Ohio. I analyzed 268 tissue samples from 25 sites along a north-south transect following the Black River between two populations with known mitochondrial clade assignment (OHnorth and PA-south clades). Ten microsatellite loci and mtDNA haplotypes were examined to characterize the genetic structure of the contact zone. Twenty-three sample sites contained only members of the PA clade, and two sites at the northern extent of the transect including the known OH clade population contained a mixture of members of both the OH and PA clades. Population structure from microsatellite data suggests a single parental population across most of the transect, with possible evidence of admixture in sites further south; however, this structure is not concordant with mtDNA clade membership. All individuals at the site exhibiting the most admixture in mtDNA 6 clade membership were assigned to the same genetic cluster of the two groups identified based on microsatellite data. Sex-biased dispersal could contribute to the mito-nuclear discordance, but more data are necessary to test this hypothesis and determine if geographic barriers also contribute to population structure. My results suggest that the contact zone extends northward toward Lake Erie, as well as west of the present sampling area, and should be further sampled to quantify the structure of the genetic cline between these two clades.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 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".