Genetic analysis of <i>Cistothorus palustris</i> (Marsh Wren) across a broad transition zone in Southern Saskatchewan reveals deep divergence and little hybridization between two cultural phenotypes
Bibliographic record
Abstract
Abstract We here explore the relationship between biological and cultural evolution in Cistothorus palustris (Marsh Wren), which across Canada and the United States can be easily differentiated into two geographic groups based on diagnostic western and eastern song types. The wren songs are culturally transmitted, as young males raised in the laboratory readily learn songs of either type. We find that, in cattail- and bulrush-dominated marshes across a &gt; 400-km transition zone in southern Saskatchewan, males of both cultural traditions occur together and defend territories against each other; pure western and pure eastern singers are abundant, and relatively few males have learned songs of both phenotypes. To determine the genetic ancestry of singing males in these two cultural traditions, we generated reduced-representation genomic sequence data for birds from across this contact zone. We find exceptionally high genome-wide divergence between western and eastern singing Marsh Wrens from outside the contact zone (FST = 0.61), potentially the highest between any lineages that form a hybrid zone in the North American Great Plains. In the heart of the contact zone, genetic data indicate an overall low rate of hybrid ancestry, and ancestry is tightly coupled with male song type, suggesting that this cultural trait could play a role in maintaining a strong but imperfect degree of assortative mating. All 9 of the mixed singers (males with both western and eastern songs) that we sequenced were of predominantly eastern ancestry, with 6 of them having 100% eastern genotype. These mismatched individuals could play an outsized role in driving the ongoing generation of hybrid offspring and the introgression of eastern alleles into western populations. Taken together, these genomic and vocal datasets reveal that the western and eastern Marsh Wren song phenotypes represent deeply divergent parapatric lineages despite breeding side-by-side in the same marshes. Although all males are capable of learning the songs of the other genotype, they rarely do, and two cultural traditions representing two genetic ancestries appear to coexist stably in the Great Plains of southern Saskatchewan.
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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 | 0.000 |
| 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".