PiggyBac transposable element derived 3, also known as PGBD3, encodes a 593 amino acid transposase and is a member of the piggyBac transposable element derived (PGBD) gene family, which includes several genes that are derived from piggyBac transposons. Initially characterized in the cabbacge looper moth, Trichoplusia ni, the PGBD family is conserved in a wide variety of species, including protozoa and primates. More specifically, while PGBD3 and PGBD4 are primate-specific genes, the other three members of the PGBD family (namely PGBD1, PGBD2 and PGBD5) are conserved among a variety of vertebrates. PGBD3 appears to be novel, with no clear relationship to other transposases or other known protein families. However, the PGBD3 gene overlaps with the CSB gene on chromosome 10 and, with the CSB gene, plays a role in Cockayne syndrome, a rare disorder characterized by premature aging, microcephaly, photosensitivity and severe neurologic degeneration.