Cornell links transposons to immunity
- Cornell researchers reported in a November 21, 2025 iScience paper that the chromatin-mapping method CUT&Tag can track transposons in genomic regions older sequencing workflows often missed. - Senior author Patrick Murphy said transposons make up about half the human genome, and the study argues many sit in the cell’s discarded “solid” fraction rather than the liquid fraction usually analyzed. - The finding adds a tool for studying mobile DNA tied to immunity, development and disease, extending work that has recast transposons as regulators rather than genomic debris. (cornell.edu)
Transposons are pieces of DNA that can copy or move themselves, which is why biologists call them “jumping genes.” In humans, they make up about half the genome. (nature.com) (cornell.edu) For decades, many of those sequences were lumped into “junk DNA” because standard lab workflows focused on the easier-to-sequence material released when cells are broken open. Cornell researchers say that approach missed much of where transposons actually sit. (cornell.edu) (eurekalert.org) In a paper published November 21, 2025 in iScience, Patrick Murphy and colleagues reported that a chromatin-profiling method called CUT&Tag can map transposons in those harder-to-study regions. The paper’s title is “CUT&Tag overcomes biases of ChIP and establishes chromatin patterns for transposons.” (cornell.edu) (cell.com) CUT&Tag is short for cleavage under targets and tagmentation. In plain terms, it tags DNA where a chosen protein mark is sitting, which lets researchers read chromatin patterns without the up-front purification steps used in older methods. (cornell.edu) (cell.com) Murphy said the study found “the solid part is where all the transposons are,” referring to the material older workflows often discarded. The Cornell release says that difference helps explain why repetitive DNA has been hard to analyze for so long. (cornell.edu) (eurekalert.org) The Cornell team did not claim that this one paper newly discovered every role transposons play in immunity or brain function. It argued that better mapping should make those roles easier to study across immune response, neurological function and genetic evolution. (cornell.edu) (phys.org) That distinction matters because the broader field had already been moving away from the “junk DNA” label. A 2025 Nature Reviews Immunology perspective said transposable elements can shape innate immune responses, T cell behavior and anti-tumor immunity. (nature.com) The same review says transposable elements can affect cells in at least three ways: by moving to new genomic sites, by producing RNA or protein when transcribed, and by acting as promoters or enhancers that regulate nearby genes. Those are the mechanisms researchers are now trying to measure more directly. (nature.com) Cornell also tied the work to older examples of transposon biology, including early development, placental function, hemophilia and some cancers. Barbara McClintock first described transposons in maize in the 1940s, work that later earned the 1983 Nobel Prize in physiology or medicine. (cornell.edu) (nature.com) So the news here is less that scientists suddenly learned transposons matter, and more that a Cornell-led paper says they can now be mapped with less bias. If that holds up across more systems, researchers will have a clearer way to study a genomic half that older methods often blurred. (cornell.edu) (cell.com)
