Format

Send to

Choose Destination
Mol Biol Evol. 2012 Dec;29(12):3767-80. doi: 10.1093/molbev/mss179. Epub 2012 Jul 19.

Evolution of viral proteins originated de novo by overprinting.

Author information

1
Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland. nsabath@gmail.com

Abstract

New protein-coding genes can originate either through modification of existing genes or de novo. Recently, the importance of de novo origination has been recognized in eukaryotes, although eukaryotic genes originated de novo are relatively rare and difficult to identify. In contrast, viruses contain many de novo genes, namely those in which an existing gene has been "overprinted" by a new open reading frame, a process that generates a new protein-coding gene overlapping the ancestral gene. We analyzed the evolution of 12 experimentally validated viral genes that originated de novo and estimated their relative ages. We found that young de novo genes have a different codon usage from the rest of the genome. They evolve rapidly and are under positive or weak purifying selection. Thus, young de novo genes might have strain-specific functions, or no function, and would be difficult to detect using current genome annotation methods that rely on the sequence signature of purifying selection. In contrast to young de novo genes, older de novo genes have a codon usage that is similar to the rest of the genome. They evolve slowly and are under stronger purifying selection. Some of the oldest de novo genes evolve under stronger selection pressure than the ancestral gene they overlap, suggesting an evolutionary tug of war between the ancestral and the de novo gene.

PMID:
22821011
PMCID:
PMC3494269
DOI:
10.1093/molbev/mss179
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Silverchair Information Systems Icon for PubMed Central
Loading ...
Support Center