The Genetic Signature of Range Expansion in a Disease Vector—The Black-Legged Tick
Bibliographic record
Abstract
Monitoring and predicting the spread of emerging infectious diseases requires that we understand the mechanisms of range expansion by its vectors. Here, we examined spatial and temporal variation of genetic structure among 13 populations of the Lyme disease vector, the black-legged tick, in southern Quebec, where this tick species is currently expanding and Lyme disease is emerging. Our objective was to identify the primary mode of tick movement into Canada based on observed spatial and temporal genetic patterns. Upon genotyping 10 microsatellite loci from 613 tick specimens, we found multiple genetic signatures of frequent long-distance dispersal events, supporting the hypothesis that migratory birds are the primary carriers of black-legged ticks into southern Quebec. When we compared results from analyses of pairwise differences among ticks collected from 8 different sites at different years between 2011 and 2014, we found that genetic variation observed among tick individuals appeared to be better explained by collection year than sampling locality. This suggests that while cohorts of black-legged ticks can rapidly invade large areas across southern Quebec, they also appear to be undergoing frequent turnover. Finally, the amount of genetic variation in tick populations across our study area appeared to be related to their degree of establishment, with established populations displaying a lower amount of temporal genetic variation than adventitious ones. Given that Lyme disease infection risk in a region can be influenced by the relative presence of established and/or adventitious tick populations, our results are useful for understanding both the seasonality and spatial variation of Lyme disease.
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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 | 0.001 |
| 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".