Molecular Evolution of Sexual and Parthenogenetic Lineages of the Armored Scale Insect <i>Aspidiotus nerii</i> (Hemiptera: Diaspididae) and Its Primary Bacterial Endosymbiont, <i>Uzinura diaspidicola</i>
Bibliographic record
Abstract
Abstract Here we compare rates of molecular evolution in sexual and parthenogenetic lineages of Aspdiotus nerii Bouché (Hemiptera: Diaspididae) using the genealogies of three protein-coding loci from A. nerii (one mitochondrial and two nuclear), and two protein-coding loci from the primary endosymbiont Uzinura diaspidicola Gruwell (Proteobacteria: Gammaproteobacteria). To our knowledge, this is the first study to examine how the loss of sex affects DNA sequence substitution rates across nuclear, mitochondrial, and endosymbiont genomes. We find no differences between ratios of nonsynonymous to synonymous substitutions (dN/dS) in sexual and parthenogenetic lineages for nuclear loci (CAD and EFlα) and endosymbiont loci (rspB and GroEL). We do find, however, for a fragment spanning portions of the mitochondrial genes cytochrome oxidase 1 and 2 (CO1-CO2) that a model including separate dN/dS ratios for the sexual and parthenogenetic lineages is a significantly better fit for the data (P = 0.003) than a model that includes a single dN/dS ratio for both lineages. We find this result striking because for asexual lineages nuclear, mictochondrial, and endosymbiont genomes share a similar mode of transmission (i.e., vertical from mother to offspring), yet our results show that elevated dN/dS ratios were only observed in the mitochondrial genome. This result supports a recent hypothesis that interactions between the endosymbiont and nuclear genomes may limit the accumulation of deleterious mutations in the endosymbiont genome, and suggests that these same interactions may influence mutation rates in the nuclear genomes of asexual organisms as well.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.001 | 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".