Genetics. Published Articles Ahead of Print: August 24, 2008, Copyright © 2008
doi:10.1534/genetics.108.089086


A more recent version of this article appeared on September 1, 2008.

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The Rate and Character of Spontaneous Mutation in Thermus thermophilus

Reena R. Mackwan 1, Geraldine T. Carver 2, Grace E. Kissling 2, John W. Drake 2 and Dennis W. Grogan 1*

1 University of Cincinnati
2 NIEHS

* To whom correspondence should be addressed. E-mail: grogandw{at}email.uc.edu.

Submitted on March 9, 2008
Revised on May 8, 2008
Accepted on 30 June 2008


Abstract

Selection of spontaneous, loss-of-function mutations at two chromosomal loci (pyrF and pyrE) enabled the first molecular-level analysis of replication fidelity in the extremely thermophilic bacterium Thermus thermophilus. Two different methods yielded similar mutation rates, and mutational spectra determined by sequencing of independent mutants revealed a variety of replication errors distributed throughout the target genes. The genomic mutation rate estimated from these targets, 0.00097±0.00052 per replication, was lower than corresponding estimates from mesophilic micro-organisms, primarily because of a low rate of base substitution. However, both the rate and spectrum of spontaneous mutations in T. thermophilus resembled those of the thermoacidophilic archaeon Sulfolobus acidocaldarius, despite important molecular differences between these two thermophiles and their genomes.

Key Words: Base-pair substitutions, Indel mutations, Mutation rate, Mutation spectrum, Thermus thermophilus