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Journal article

Selection-driven cost-efficiency optimization of transcripts modulates gene evolutionary rate in bacteria

Abstract:

Background

Most amino acids are encoded by multiple synonymous codons. However, synonymous codons are not used equally, and this biased codon use varies between different organisms. It has previously been shown that both selection acting to increase codon translational efficiency and selection acting to decrease codon biosynthetic cost contribute to differences in codon bias. However, it is unknown how these two factors interact or how they affect molecular sequence evolution.

Results

Through analysis of 1,320 bacterial genomes we show that bacterial genes are subject to multi-objective selection-driven optimization of codon use. Here, selection acts to simultaneously decrease transcript biosynthetic cost and increase transcript translational efficiency, with highly expressed genes under the greatest selection. This optimization is not simply a consequence of the more translationally efficient codons being less expensive to synthesize. Instead, we show that tRNA gene copy number alters the cost-efficiency trade-off of synonymous codons such that for many species, selection acting on transcript biosynthetic cost and translational efficiency act in opposition. Finally, we show that genes highly optimized to reduce cost and increase efficiency show reduced rates of synonymous and non-synonymous mutation.

Conclusions

This analysis provides a simple mechanistic explanation for variation in evolutionary rate between genes that depends on selection-driven cost-efficiency optimization of the transcript. These findings reveal how optimization of resource allocation to mRNA synthesis is a critical factor that determines both the evolution and composition of genes.

Publication status:
Published
Peer review status:
Peer reviewed

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Publisher copy:
10.1186/s13059-018-1480-7

Authors

More by this author
Institution:
University of Oxford
Division:
MPLS Division
Department:
Plant Sciences
Role:
Author
More by this author
Institution:
University of Oxford
Division:
MPLS
Department:
Plant Sciences
Role:
Author
ORCID:
0000-0001-8583-5362


Publisher:
BioMed Central
Journal:
Genome Biology More from this journal
Volume:
19
Pages:
102
Publication date:
2018-07-31
Acceptance date:
2018-06-05
DOI:
EISSN:
1465-6906
ISSN:
1474-760X


Keywords:
Pubs id:
pubs:856196
UUID:
uuid:06d35b3e-9072-400e-80c1-2bd520f79512
Local pid:
pubs:856196
Source identifiers:
856196
Deposit date:
2018-06-06
ARK identifier:

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