Shaping species with ephemeral boundaries: the distribution and genetic structure of desert tortoise (<i>Gopherus morafkai</i>) in the Sonoran Desert region
Bibliographic record
Abstract
Abstract Aim We examine the role biogeographical features played in the evolution of Morafka's desert tortoise ( Gopherus morafkai ) and test the hypothesis that G. morafkai maintains genetically distinct lineages associated with different Sonoran Desert biomes. Increased knowledge of the past and present distribution of the Sonoran Desert region's biota provides insight into the forces that drive and maintain its biodiversity. Location Sonoran Desert biogeographical region; Sonora and Sinaloa, Mexico and Arizona, USA. Methods We examined wild tortoises from Mexico ( n = 155) and Arizona ( n = 78), spanning their known distribution. We used mt DNA sequences to reconstruct matrilineal relationships and 25 microsatellite ( STR ) loci for Bayesian analyses of gene flow. We performed clinal analyses on both mt DNA and STR loci to determine the position and amount of introgression where lineages co‐occur. We used GIS to assess the association of genetic structuring with ecological features. We used these data in a hypothesis‐driven approach to assess different models of how genetic diversity is maintained and distributed in G. morafkai . Results Gopherus morafkai was found to comprise genetically and geographically distinct ‘Sonoran’ and ‘Sinaloan’ lineages. Both lineages occurred in a relatively narrow zone of overlap in Sinaloan thornscrub, where it transitions into Sonoran desertscrub. Limited introgression occurred at the contact zone. The best‐fit model suggests that these lineages diverged in parapatry where the distribution of genotypes is environment‐dependent and introgression is inhibited by exogenous selection. Main conclusions The historically shifting ecotone between tropical deciduous forest and Sonoran desertscrub appears to be a boundary that fostered divergence between parapatric lineages of tortoises. The sharp genetic cline between the two lineages suggests that periods of isolation in temporary refugia due to Pleistocene climatic cycling influenced divergence. Despite incomplete reproductive isolation, the Sonoran and Sinaloan lineages of G. morafkai are on separate evolutionary trajectories.
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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 | 0.001 |
| 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".