Genomic Analysis Reveals Subdivision of Black Rats (Rattus rattus) in India, Origin of the Worldwide Species Spread
Bibliographic record
Abstract
In contrast to the detailed and globally extensive studies on the spread of the commensal black rat, Rattus rattus, there has been relatively little work on the phylogeography of the species within India, from where this spread originated. Taking a genomic approach, we typed 27 R. rattus samples from Peninsular India using the genotyping-by-sequencing (GBS) method. Filtering and alignment of the FASTQ files yielded 1499 genome-wide SNPs. Phylogenomic tree reconstruction revealed a distinct subdivision in the R. rattus population, manifested as two clusters corresponding to the east and west coasts of India. We also identified signals of admixture between these two subpopulations, separated by an Fst of 0.20. This striking genomic difference between the east and west coast populations mirrors what has previously been described with mitochondrial DNA sequencing. It is notable that the west coast population of R. rattus has been spread globally, reflecting the origins of commensalism of the species in Western India and the subsequent transport by humans worldwide.
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| 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".