Natural Selection and the Origin of jingwei , a Chimeric Processed Functional Gene in Drosophila

The origin of new genes includes both the initial molecular events and subsequent population dynamics. A processed Drosophila alcohol dehydrogenase ( Adh ) gene, previously thought to be a pseudogene, provided an opportunity to examine the two phases of the origin of a new gene. The sequence of the processed Adh messenger RNA became part of a new functional gene by capturing several upstream exons and introns of an unrelated gene. This novel chimeric gene, jingwei , differs from its parent Adh gene in both its pattern of expression and rate of molecular evolution. Natural selection participated in the origin and subsequent evolution of this gene.