Divergent lineages in a young species: the case of Datilillo ( <i>Yucca valida</i> ), a broadly distributed plant from the Baja California Peninsula
Bibliographic record
Abstract
ABSTRACT Premise Globally, barriers triggered by climatic changes have caused habitat fragmentation and population allopatric divergence. Across North America, oscillations during the Quaternary have played important roles in the distribution of wildlife. Notably, diverse plant species from the Baja California Peninsula, in western North America, exhibit strong genetic structure and highly concordant divergent lineages across their ranges, as they were isolated during the Pleistocene glacial-interglacial cycles and thus accumulated genetic differentiation in their genomes. A representative plant genus of this Peninsula is Yucca , with Yucca valida having the widest range. Whereas Y. valida is a dominant species, there is an extensive distribution discontinuity between 26° N and 27° N, where no individuals have been identified, suggesting restricted gene flow. Moreover, the historical distribution models indicate the absence of an area with suitable conditions for the species during the Last Interglacial, making it an interesting model for studying genetic divergence. Methods We examined the phylogeography of Y. valida throughout its range to identify the number of genetic lineages, quantify their genetic differentiation, reconstruct their demographic history and estimate the species’ age. Key results We assembled 4,411 SNPs from 147 plants, identifying three allopatric lineages. Our analyses support that genetic drift is the driver of genetic differentiation among these lineages. We estimated an age under one million years for the common ancestor of Y. valida and its sister species. Conclusions Habitat fragmentation caused by climatic changes, low dispersal, and an extensive geographical range gap acted as cumulative mechanisms leading to allopatric divergence in Y. valida .
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 | 0.001 |
| 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 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| 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".