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Stop codon reassignments in the wild

Science  23 May 2014:
Vol. 344, Issue 6186, pp. 909-913
DOI: 10.1126/science.1250691

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Abstract

The canonical genetic code is assumed to be deeply conserved across all domains of life with very few exceptions. By scanning 5.6 trillion base pairs of metagenomic data for stop codon reassignment events, we detected recoding in a substantial fraction of the >1700 environmental samples examined. We observed extensive opal and amber stop codon reassignments in bacteriophages and of opal in bacteria. Our data indicate that bacteriophages can infect hosts with a different genetic code and demonstrate phage-host antagonism based on code differences. The abundance and diversity of genetic codes present in environmental organisms should be considered in the design of engineered organisms with altered genetic codes in order to preclude the exchange of genetic information with naturally occurring species.

In translation, sometimes stop can mean go

The genetic code appears to be largely conserved across all domains of life. Although limited deviations have been reported, Ivanova et al. used metagenomics to survey the prevalence of stop codon reassignment in naturally occurring microbial populations. Certain bacteria and bacteriophages exhibited lineage-specific recoding of their stop codons. In one specific phage, the genome was restructured into two genetic sets. One set of genes was encoded in a way that didn't gel with the host genome and probably helped with infection. A second set of more host-compatible sequences encoded proteins expressed in the later stages of infection.

Science, this issue p. 909

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