Evolution of Viral Proteins Originated De Novo by Overprinting

Sabath, Niv; Wagner, Andreas; Karlin, David

In closing, we point to several directions for future research. Approaches to estimate selection pressures in overlapping genes (e.g., Sabath et al. 2008 ) lag behind those for nonoverlapping genes (reviewed in Anisimova and Kosiol 2009) , which can detect lineage-specific and site-specific selection pressures. The development of advanced methods could, for instance, reveal the role of positive selection in de novo gene origination and perhaps predict interactions between proteins encoded by overlapping genes, such as the Rz and Rz1 genes of bacteriophage lambda (Zhang and Young 1999) . Finally, further research is needed to shed light on how exactly de novo overlapping genes originate and become established, i.e., the mutational events that result in their expression, their frequency, and their effects on viral fitness.