Summary
A bioRxiv preprint analysing 231 haplotype-resolved human pangenomes reports that variable transposable elements can gain, change or lose regulatory effects before they become fixed. Their effects depend on DNA methylation and transcript context.
A bioRxiv preprint analysing 231 haplotype-resolved human pangenomes reports that transposable-element variants can affect gene regulation while they are still present in some genomes and absent in others. The authors combined long-read data with matched molecular measurements to examine element sequences, epigenetic states and transcript components. They conclude that regulatory evolution can involve gains, changes and losses—not just the gradual accumulation of useful insertions.
Following elements before they become fixed
Transposable elements are DNA sequences with an evolutionary history of copying or moving within genomes. Some insertions are shared across a population; others vary, or are polymorphic: present in some genomes and absent in others. Over time, a variant may become fixed in a population or disappear. The authors say these earlier, variable stages have been difficult to study because the elements were often scored only as present or absent.
A pangenome represents genomic sequences across multiple individuals rather than relying on a single reference. The study used 231 haplotype-resolved human pangenomes, with matched long-read multi-omics, to examine the variable elements in greater detail. Haplotype-resolved data keep the two inherited chromosome copies distinct, helping researchers track which sequence version carries an element. The authors report that the elements’ origins extend beyond recent transposition, so their presence in a genome does not necessarily mean they inserted recently.
Regulatory effects depend on context
The authors report that an element’s regulatory consequences depend on its methylation state and transcript context. DNA methylation is a chemical modification of DNA that can influence gene activity. The study also examined whether element sequences formed part of transcripts—the RNA molecules made from genomic instructions. Looking only at gene-level measurements can miss these effects, the authors say, because the regulatory change may be apparent in the transcript details rather than as a simple change in a gene’s overall output.
The preprint also identifies transposable elements as possible regulatory mechanisms at trait-associated genomic loci. These are regions linked to measured traits; their presence in the analysis offers a route for investigating how genetic variation may affect regulation, but does not by itself establish that an element causes a particular trait.
The authors report that selection can favour both element-bearing and element-absent variants. This supports a view of regulatory evolution as context-dependent: an insertion may add a regulatory function, alter an existing one or be lost, rather than representing a one-way gain. The work is a bioRxiv preprint, and its abstract does not provide effect sizes or examples of the individual trait-associated loci.