Corn's genetic defense system sometimes silences its own good genes
Kalmykova A, Lisch D, Blumenstiel JP
Crop Improvement
The wild variation you see in heirloom corn kernels or the sudden color changes in your garden flowers can trace back to this ancient genome policing system misfiring on the plant's own genes.
Every plant's DNA contains old genetic parasites called transposable elements, first discovered in corn, that can copy themselves and cause harmful mutations if left unchecked. Plants and animals fight back with a molecular immune system that uses small RNA molecules to detect and silence these troublemakers. This defense isn't perfect: it sometimes silences nearby genes too, and that accidental collateral damage has ended up driving new patterns of inheritance and even changing how evolution shapes the defense system itself.
Key Findings
Transposable elements, first characterized in maize, can replicate independently of the host genome's own replication cycle, sometimes coming to dominate genome size.
Argonaute proteins guided by small RNAs form the core genome defense system that distinguishes self DNA from transposable element DNA in eukaryotes.
Off-target silencing from this defense system, studied mainly in maize and Drosophila, can inadvertently affect nearby genes, creating new pathways for epigenetic inheritance and evolutionary feedback.
chevron_right Technical Summary
Plants and animals have internal immune systems that silence 'jumping genes' before they cause damage, but this defense sometimes misfires and shuts down useful genes by mistake, shaping how species evolve over time.
Abstract Preview
Original paper
Transposable Elements and the Impact of Genomic Autoimmunity.
Transposable elements (TEs), originally characterized in maize, are ubiquitous features of eukaryotes and replicate within genomes independent of the host replication cycle. This replicative advant...
open_in_new Read full abstractAbstract copyright held by the original publisher.
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