Researchers at Cornell University made the discovery after identifying human genetic material inside molluscum contagiosum virus (MCV), a poxvirus. Their analysis showed that the element, known as BC200, is associated with brain function and can behave like a jumping gene—moving and inserting itself into new locations in the genome.

Research results announced on September 24 and published in Science show that BC200 combines traits scientists have not previously seen together in a human gene.

BC200 is a brain gene with a mobile genetic past

BC200 is primarily expressed in neurons, but its evolutionary history goes back millions of years to transposons. Also known as “jumping genes,” transposons are non-coding genetic elements that can rearrange themselves and insert copies into new locations in the genome.

Transposons can be harmful when they insert DNA into genes and disrupt their normal function, potentially contributing to disease. However, they can also be beneficial over evolutionary timescales. Their activity may help regulate existing genes or provide genetic material that eventually becomes part of new and useful genes.

Approximately half of the human genome is composed of DNA derived from transposons. Most of these elements are no longer active, and only a small number can still move or copy themselves within the genome.

“Genes that are derived from transposable elements and are reused for cellular functions are usually non-transposable,” said Cedric Fechotte, senior author of the study. “BC200 itself was created from a mobile element, but it maintains its mobility and also clearly serves a cellular function. For some reason, evolution has not been able to disentangle these two elements.”

How BC200 moved into a virus

Scientists have recorded several cases in other species in which transposable elements were transferred to viruses. One early example occurred in the late 1980s, when researchers working with cultured moth cells observed transposons moving from those cells into baculoviruses, a group of viruses that infect insects.

BC200, however, is found only in primates, the group of animals most closely related to humans. Scientists first identified it in the late 1980s as a highly abundant non-coding RNA in human neurons.

Although its precise physiological role remains unknown, evidence suggests that BC200 may help regulate how neuronal messenger RNA is translated into protein.

BC200 is also present at low levels in reproductive cells, including sperm and eggs. This means that new BC200 insertions could potentially occur in the genome and be passed on to future generations.

Could BC200 affect skin cells and disease?

The researchers believe BC200 may have entered skin cells while molluscum contagiosum virus was infecting them. MCV is notable because it is the only virus known to carry BC200-related human genetic material.

The gene has attracted attention because it is abnormally expressed in some tumors and appears at high levels in the brains of people with Alzheimer’s disease. These findings have raised the possibility that BC200’s ability to move through the genome could also be involved in disease.

Fechotte said the research team now wants to determine whether molluscum contagiosum virus uses BC200 to manipulate human host cells for its own benefit.

The researchers also plan to investigate BC200’s connection to diseases such as breast cancer and other tumors in which the gene is abnormally expressed. A key question is whether BC200 is actively moving within cancer cells and, if so, whether that movement causes mutations.