2024/09/11 by Alba Marino, Gautier Debaecker, Anna-Sophie Fiston-Lavier +2 · 1 voice · 12 citations
Agricultural and Biological Sciences · Biochemistry, Genetics and Molecular Biology · #Biology #Chromosomal and Genetic Variations #Demography #Effective population size #Evolutionary biology #Gene #Genetic and Environmental Crop Studies #Genetic variation #Genetics #Genome #Genome size #Genomics and Phylogenetic Studies #Physics #Population #Population size #Sociology #Term (time) #Transposable element #Variation (astronomy)
paper · pdf · doi:10.7554/elife.100574
published in eLife 13 (eLife Sciences Publications Ltd)
openalex publication_date 2024/09/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Animal genomes exhibit a remarkable variation in size, but the evolutionary forces responsible for such variation are still debated. As the effective population size (Ne e ) reflects the intensity of genetic drift, it is expected to be a key determinant of the fixation rate of nearly-neutral mutations. Accordingly, the Mutational Hazard Hypothesis postulates lineages with low Ne e to have bigger genome sizes due to the accumulation of slightly deleterious transposable elements (TEs), and those with high Ne e to maintain streamlined genomes as a consequence of a more effective selection against TEs. However, the existence of both empirical confirmation and refutation using different methods and different scales precludes its general validation. Using high-quality public data, we estimated genome size, TE content, and rate of non-synonymous to synonymous substitutions (dN/dS) as Ne e proxy for 807 species including vertebrates, molluscs, and insects. After collecting available life-history traits, we tested the associations among population size proxies, TE content, and genome size, while accounting for phylogenetic non-independence. Our results confirm TEs as major drivers of genome size variation, and endorse life-history traits and dN/dS as reliable proxies for Ne e . However, we do not find any evidence for increased drift to result in an accumulation of TEs across animals. Within more closely related clades, only a few isolated and weak associations emerge in fishes and birds. Our results outline a scenario where TE dynamics vary according to lineage-specific patterns, lending no support for genetic drift as the predominant force driving long-term genome size evolution in animals.