Scientists at Cornell University have uncovered a unique genetic feature in a poxvirus that combines two rare traits: it is both essential for brain function and a "jumping gene" capable of moving within the genome. A study published in Science describes the gene, called BC200, which is primarily expressed in neurons but originated millions of years ago from a transposon, or "jumping gene." These are noncoding genetic elements that can move and insert themselves into the DNA of organisms. While transposons can disrupt genes and cause disease, they can also contribute to evolution by creating new genetic functions. BC200 is unusual because it has retained the ability to move, or "jump," while also being necessary for normal bodily functions. Typically, genes that evolve from transposons lose their mobility once they are repurposed for cellular tasks. However, BC200 remains active in this regard. Cedric Feschotte, a senior author of the study, noted that "evolution hasn't been able to untangle these two things," meaning the gene continues to move while also serving a critical role in the brain. The research team includes Cheng Sun from Capital Normal University in Beijing and Ellen Pritham, who was based at the University of Texas at Arlington when the work was initially conducted. The discovery of BC200 dates back to 2010, when Cheng Sun was a postdoctoral researcher in Feschotte’s and Pritham’s lab. At the time, Cheng identified two instances of BC200 in a molluscum contagiosum virus (MCV), a mild poxvirus that causes warts in humans. Although the team recognized the significance of the finding, they did not publish a paper at the time. Recently, after reconnecting at a conference, Feschotte and Cheng revisited the work, leading to the current publication. BC200 is believed to have originated from a transposon that was incorporated into the genome of a common primate ancestor around 40 million years ago. Since then, it has "jumped" into the MCV virus twice in modern human history, approximately 100,000 years ago. This is not the first time transposons have been found in viruses. In the 1980s, scientists observed a transposon from moth cells inserting itself into a virus that infects insects. More recently, in 2007, researchers discovered a transposon from a snake embedded in a rodent poxvirus, suggesting the possibility of cross-species transmission. BC200 is found only in humans and related primates and was first identified in the 1980s as a noncoding RNA in neurons. Its exact function is still unclear, but it may play a role in regulating protein production in brain cells. It is also present in low levels in germ cells, suggesting it could potentially cause heritable genetic changes. The gene has been found in some tumors and is overexpressed in the brains of Alzheimer’s patients, hinting at possible links to disease. Researchers are now investigating whether the MCV virus uses BC200 to influence human cells and whether the gene contributes to cancer development.