Patterns of Amino Acid Evolution in the Drosophila ananassae Chimeric Gene, siren, Parallel Those of Other Adh-Derived Chimeras

siren1 and siren2 are novel alcohol dehydrogenase (Adh)-derived chimeric genes in the Drosophila bipectinata complex. D. ananassae, however, harbors a single homolog of these genes. Like other Adh-derived chimeric genes, siren evolved adaptively shortly after it was formed. These changes likely shifted the catalytic activity of siren.