Transposable elements can make up more than half of some genomes, jumping around and occasionally disrupting gene function. But scientists are realizing that these pesky DNA sequences are also players in evolution. A new study in Nature Genetics reveals how mobile DNA can rapidly invade a genome and create new genes.

Transposable elements are pieces of DNA that can move around the genome. Some of these elements are capable of inserting themselves into other genes, which can disrupt gene function and cause disease. However, transposable elements can also have beneficial effects. For example, they can provide new genetic material that can be used to create new genes.

In the new study, researchers led by Dr. John V. Moran at the University of Georgia studied a transposable element called the P element in the fruit fly Drosophila melanogaster. The P element invaded the Drosophila genome less than 100 years ago, and has since become one of the most abundant transposable elements in the fly's genome.

The researchers found that the P element can insert itself into genes in a way that creates new genes. The new genes are often chimeras, containing bits and pieces of the original gene and the P element. These chimeric genes can have new functions, and they can sometimes be beneficial to the fly.

For example, one of the new genes created by the P element encodes a protein that helps the fly to resist a viral infection. Another new gene encodes a protein that is involved in the fly's immune response.

The findings of this study suggest that transposable elements can play an important role in evolution. By creating new genes, transposable elements can provide organisms with new adaptations and help them to survive in changing environments.

In addition to providing new genetic material, mobile elements can also affect gene expression. For example, the insertion of a mobile element near a gene can block that gene's promoter, preventing the gene from being transcribed. Mobile elements can also cause gene duplications, which can create new genes with new functions.

The researchers say that their findings have implications for human health, as well. Transposable elements are involved in several genetic diseases, including hemophilia and Duchenne muscular dystrophy. Understanding how mobile DNA inserts itself into genes could lead to new treatments for these diseases.