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Genome Evolution in Amphibians

2020· other· en· W3029637856 on OpenAlexaff
John H. Herrick, Bianca Sclavi

Bibliographic record

VenueEncyclopedia of Life Sciences · 2020
Typeother
Languageen
FieldAgricultural and Biological Sciences
TopicChromosomal and Genetic Variations
Canadian institutionsSimon Fraser University
Fundersnot available
KeywordsBiologyGenome sizeGenomeEvolutionary biologyGenome evolutionEukaryoteGeneticsVertebrateMitochondrial DNAGene

Abstract

fetched live from OpenAlex

Abstract Genome size variation in vertebrates reflects an amazing amount of genetic and genomic diversity. C‐value (genome size) ranges from 0.4 picograms (pg) in pufferfish to 133 pg in the marbled lungfish. Most vertebrate lineages have characteristic average C‐values with restricted ranges. Amphibia, in contrast, represent an extreme: C‐values in salamanders range from around 13 to over 122 pg; in frogs, they range from under 1 to over 13 pg. Why would closely related lineages and species have such dramatic differences in C‐value? A number of theories have been proposed to account for the extreme range in genome size found in all eukaryote taxa. The amphibia not only have a wide range of C‐values, but they also have a correspondingly wide range of life history traits and other phenotypes such as neoteny and limb regeneration. This remarkable class of vertebrate thus provides a unique model system for addressing evolutionary and physiological hypotheses. Key Concepts Junk DNA (retroviruses and DNA transposons) infected the ancestral eukaryote cell and established, together with mitochondria, a symbiotic relationship from which all other eukaryotic life forms emerged. The host response to the original infection was adaptive rather than purifyingly selective: junk DNA provided the conditions for the emergence of a checkpoint guardian of the genome and correspondingly enhanced genome stability. As genome size expanded, DNA repair systems increased in efficiency, allowing for the acquisition of new genes and new adaptations. DNA replication programs and gene transcription programs reorganised as genome size either increased or decreased over evolutionary time. Species richness negatively correlates with genome stability and positively correlates with karyotype diversity within specific lineages. DNA damage response and repair (DDR) programs have evolved differentially in r and K‐strategists: large body organisms have enhanced DDRs compared to small body, short‐lived organisms, and hence they tend to have more deterministic and organised replication programs. Junk DNA serves as a substrate for the DDR to protect the cell against ‘mitotic catastrophe’. Junk DNA serves as a scaffold for the formation of facultative heterochromatin during development and speciation,and hence participates in the global tissue‐specific and species‐dependent transcription programs.

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 imitation

Not 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.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Not applicable · Consensus signal: none
GenreCandidate signal: Other · Consensus signal: none
Teacher disagreement score0.003
Threshold uncertainty score0.009

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0010.001
Science and technology studies0.0000.000
Scholarly communication0.0010.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0030.000

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.

Opus teacher head0.016
GPT teacher head0.218
Teacher spread0.203 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designNot applicable
Domainnot available
GenreOther

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".

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Citations2
Published2020
Admission routes1
Has abstractyes

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