Biology subjects

Caillieux, E.

Publications and source records attributed to Caillieux, E..

4 recordsLinked to original sources

bioRxiv2026

Fragmented landscapes of mobile transposable element families bolster the diversity of large-effect alleles in Arabidopsis

Transposable elements (TEs) are powerful endogenous mutagens, but our understanding of the 'mobilome' - the set of mobile TEs at the species level - has largely been shaped by the study of a single reference genome. To overcome this reference-centric view, we produced long-read genome assemblies for 91 Arabidopsis thaliana strains and performed a reference-free pangenomic graph analysis of structural variants. Our analysis revealed the presence of twice as many TE families with recent mobilization activity as previously described. These >200 newly identified TE families are ancestral, with a third experimentally shown to be mobile and although they are often characterized by the presence of full-length copies in only a few rather than in most strains, they nonetheless contribute significantly to the generation of large-effect alleles. These findings uncover a much more fragmented and impactful mobilome than previously documented and highlight how pangenome approaches dramatically improve the study of genetic diversity.

genomics↗

bioRxiv2024

The 1001G+ project: A curated collection of Arabidopsis thaliana long-read genome assemblies to advance plant research

Arabidopsis thaliana was the first plant for which a high-quality genome sequence became available. The publication of the first reference genome sequence almost 25 years ago was already accompanied by genome-wide data on sequence polymorphisms in another accession, or naturally occurring strain. Since then, inventories of genome-wide diversity have been generated at increasingly precise levels. High-density genotype data for A. thaliana, including those from the 1001 Genomes Project, were key to demonstrating the enormous power of GWAS in inbred populations of wild plants, and the comparison of intraspecific polymorphism with interspecific divergence has illuminated many aspects of plant genome evolution. Over the past decade, an increasing number of nearly complete genome sequences have been published for many more accessions. Here, we highlight the diversity of a curated collection of previously published and so far unpublished genome sequences assembled using different types of long reads, including PacBio Continuous Long Reads (CLR), PacBio High Fidelity (HiFi) reads, and Oxford Nanopore Technologies (ONT) reads. This 1001 Genomes Plus (1001G+) resource is being made available at http://1001genomes.org. We invite colleagues with yet unpublished genome assemblies from A. thaliana accessions to contribute to this effort.

genomics↗

bioRxiv2024

Transposable elements are prevalent vectors of transgenerational epigenetic inheritance in nature

Loss of DNA methylation over transposable elements (TEs) can affect neighboring genes and be epigenetically inherited in plants, yet the determinants and significance of this additional system of inheritance are unknown. Here, we demonstrate at thousands of TE loci across the Arabidopsis thaliana genome, that experimentally-induced hypomethylation can be transmitted transgenerationally and reveal the role of small RNAs derived from related copies in counteracting this transmission. Using data from >700 strains collected worldwide, we uncover natural hypomethylation at hundreds of the same TE loci, often situated near stress-responsive genes. Like their experimental counterparts, most natural epivariants we tested can be inherited without DNA sequence changes and are therefore bona fide epialleles, although genetic factors modulate their recurrence or persistence. Crucially, we demonstrate that TE-mediated epiallelic variation associated with differential gene expression is generally causal and may be target of selection in specific environments, thus establishing its importance in nature.

genomics↗

bioRxiv2018

Transposon accumulation lines uncover histone H2A.Z-driven integration bias towards environmentally responsive genes

Inherited transposition events are important drivers of genome evolution but because transposable element (TE) mobilization is usually rare, its impact on the creation of genetic variation remains poorly characterized. Here, we used a population of A. thaliana epigenetic recombinant inbred lines (epiRILs) to characterize >8000 de novo insertions produced by several TEs families also active in nature. Integration was strongly biased towards genes, with evident deleterious effects. Biases were TE family-specific and associated with distinct chromatin features. Notably, we demonstrate that the histone variant H2A.Z guides the preferential integration of Ty1/Copia LTR-retrotransposons within environmentally responsive genes and that this guiding function is evolutionary conserved. Finally, we uncover an important role for epigenetic silencing in exacerbating or alleviating the effects of TE insertions on target genes. These findings establish chromatin as a major determinant of the spectrum and functional impact of TE-generated mutations, with important implications for adaptation and evolution.

genomics↗