TY - JOUR
T1 - The insect-killing bacterium Photorhabdus luminescens has the lowest mutation rate among bacteria
AU - Pan, Jiao
AU - Williams, Emily
AU - Sung, Way
AU - Lynch, Michael
AU - Long, Hongan
N1 - Funding Information:
This work is supported by the Young Taishan Scholars Program of Shandong Province (tsqn201812024), the Fundamental Research Funds for the Central Universities of China (201822020) to H.L., the Multidisciplinary University Research Initiative Award from the US Army Research Office (W911NF-09-1-0444 and W911NF-09-1-0411) and National Institutes of Health award (R35-GM122566) to M.L. We thank Wei Yang (IEMB-1 cluster administrator) and Kun Wu for their technical help.
Publisher Copyright:
© 2020, The Author(s).
PY - 2021/2
Y1 - 2021/2
N2 - Mutation is a primary source of genetic variation that is used to power evolution. Many studies, however, have shown that most mutations are deleterious and, as a result, extremely low mutation rates might be beneficial for survival. Using a mutation accumulation experiment, an unbiased method for mutation study, we found an extremely low base-substitution mutation rate of 5.94 × 10–11 per nucleotide site per cell division (95% Poisson confidence intervals: 4.65 × 10–11, 7.48 × 10–11) and indel mutation rate of 8.25 × 10–12 per site per cell division (95% confidence intervals: 3.96 × 10–12, 1.52 × 10–11) in the bacterium Photorhabdus luminescens ATCC29999. The mutations are strongly A/T-biased with a mutation bias of 10.28 in the A/T direction. It has been hypothesized that the ability for selection to lower mutation rates is inversely proportional to the effective population size (drift-barrier hypothesis) and we found that the effective population size of this bacterium is significantly greater than most other bacteria. This finding further decreases the lower-bounds of bacterial mutation rates and provides evidence that extreme levels of replication fidelity can evolve within organisms that maintain large effective population sizes.
AB - Mutation is a primary source of genetic variation that is used to power evolution. Many studies, however, have shown that most mutations are deleterious and, as a result, extremely low mutation rates might be beneficial for survival. Using a mutation accumulation experiment, an unbiased method for mutation study, we found an extremely low base-substitution mutation rate of 5.94 × 10–11 per nucleotide site per cell division (95% Poisson confidence intervals: 4.65 × 10–11, 7.48 × 10–11) and indel mutation rate of 8.25 × 10–12 per site per cell division (95% confidence intervals: 3.96 × 10–12, 1.52 × 10–11) in the bacterium Photorhabdus luminescens ATCC29999. The mutations are strongly A/T-biased with a mutation bias of 10.28 in the A/T direction. It has been hypothesized that the ability for selection to lower mutation rates is inversely proportional to the effective population size (drift-barrier hypothesis) and we found that the effective population size of this bacterium is significantly greater than most other bacteria. This finding further decreases the lower-bounds of bacterial mutation rates and provides evidence that extreme levels of replication fidelity can evolve within organisms that maintain large effective population sizes.
KW - Drift-barrier hypothesis
KW - Lower-limit of mutation rate
KW - Mutation accumulation
KW - Mutation spectrum
KW - Neutral evolution
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U2 - 10.1007/s42995-020-00060-0
DO - 10.1007/s42995-020-00060-0
M3 - Article
AN - SCOPUS:85112477192
SN - 2096-6490
VL - 3
SP - 20
EP - 27
JO - Marine Life Science and Technology
JF - Marine Life Science and Technology
IS - 1
ER -