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Real-Time Quantification of the Effects of IS200/IS605 Family-Associated TnpB on Transposon Activity
Published on: January 20, 2023
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Effective population size does not explain long-term variation in genome size and transposable element content in
Alba Marino1, Gautier Debaecker2, Anna-Sophie Fiston-Lavier1,3
1ISEM, Université de Montpellier, CNRS, IRD, Montpellier, France.
Elife
|July 18, 2025
Summary
Genetic drift does not drive genome size evolution in animals. Transposable elements (TEs) are key drivers, but their accumulation is lineage-specific, not linked to effective population size (Nee).
Area of Science:
- Evolutionary Biology
- Genomics
- Population Genetics
Background:
- Animal genome sizes vary significantly, with evolutionary drivers debated.
- The Mutational Hazard Hypothesis links effective population size (Nee) to genome size via transposable element (TE) accumulation.
- Previous studies offer conflicting evidence, hindering general validation of the hypothesis.
Purpose of the Study:
- To investigate the relationship between effective population size (Nee), transposable element (TE) content, and genome size variation across diverse animal lineages.
- To test the Mutational Hazard Hypothesis using robust proxies for Nee and large-scale genomic data.
Main Methods:
- Analyzed genome size, TE content, and non-synonymous to synonymous substitution rates (dN/dS) as a proxy for Nee in 807 animal species.
- Incorporated life-history traits as additional Nee proxies.
- Employed phylogenetic comparative methods to account for evolutionary relatedness.
Main Results:
- Transposable elements (TEs) are confirmed as major contributors to genome size variation.
- Life-history traits and dN/dS rates serve as reliable proxies for effective population size (Nee).
- No evidence supports increased genetic drift leading to TE accumulation across animals; associations are weak and lineage-specific.
Conclusions:
- Genetic drift is not the predominant force shaping long-term animal genome size evolution.
- Transposable element (TE) dynamics are influenced by lineage-specific factors rather than solely by effective population size (Nee).
- Genome streamlining is not universally achieved through strong selection against TEs in high Nee lineages.
Keywords:
evolutionary biologygeneticsgenome size evolutiongenomicsmutational hazard hypothesistransposable elementsMore Related Videos
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