Bibliographic record
Abstract
Abstract A mutation is a heritable change in the genetic material that is not due to genetic recombination. All current genetic variation existing within and among populations originated by mutation in ancestral individuals. Mutations may occur at any stage of the cell cycle, but most probably arise during cell division. Mutations can change the structure or number of single nucleotide sites, multiple nucleotides, entire chromosomes or the entire genome. The vast majority of mutations with fitness effects are mildly harmful; very few are beneficial. The rate of mutation results from the difference between rate of input and repair of nucleic acid lesions. Mutation rates differ among organisms and can evolve like other traits from the influence of selection and drift. Taxa with larger population sizes tend to have lower mutation rates per coding DNA per generation, suggesting that selection is less effective at lowering the rate in small populations. Accurate measures of the beneficial and deleterious mutation rates, the environmental factors affecting mutation and how mutation rates evolve in different organisms are all active areas of research in evolutionary biology. Key Concepts A mutation is a heritable change in the genetic material that is not due to genetic recombination. Mutations are the ultimate source of all genetic differences within and among species. Types of mutation include replacements, insertions and deletions of single nucleotides as well as gains or losses of chromosome segments or entire chromosomes. Most mutations have no detectable phenotypic effect and are neutral or very slightly deleterious with respect to fitness. The vast majority of mutations affecting fitness are deleterious. Mutation rates per nucleotide can differ as a result of genome size, neighbouring base composition, population size, sex, age and environmental conditions. Mutation rates themselves can evolve. The existence of mutations in a population creates a ‘genetic mutational load’, which is defined as the fraction by which the average fitness of individuals in a population is reduced because of mutations. Nucleotide‐substitution mutation rates range from ∼0.08 × 10 −9 to 9.8 × 10 −9 per site per cell division in prokaryotes (bacteria and archaea) and from ∼0.5 × 10 −9 to 50 × 10 −9 per site per generation in eukaryotes. Human children differ from their parents at approximately 60–70 point mutations, or about one mutation per 100 megabases (Mb).
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 | 0.002 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.005 | 0.004 |
| Science and technology studies | 0.001 | 0.004 |
| Scholarly communication | 0.003 | 0.005 |
| Open science | 0.002 | 0.003 |
| Research integrity | 0.003 | 0.004 |
| Insufficient payload (model declined to judge) | 0.008 | 0.002 |
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".