of Work: Rates of spontaneous mutation vary greatly among organisms. We have previously described genomic mutation rates that are characteristic of certain broad groups of organisms. For instance, riboviruses have genomic mutation rates of 0.1?1 per replication, a value approaching the maximum compatible with survival. The characteristic genomic mutation rate for DNA-based microbes is about 0.003 per replication. Because the generality of this rule has not been tested in a mammalian viral pathogen, we are investigating the mutation process in herpes simplex virus. In the Archaeon Sulfolobus acidocaldarius growing at 75 degrees C, the mutation rate is close to 0.003 but the proportion of base-pair substitutions is lower than in all other DNA-based organisms. We hypothesized that the average missense mutation has a greater deleterious effect at high temperatures. As a result, evolutionary pressures would act to decrease base-substitution mutation rates. One prediction of this hypothesis is that a thermophilic eubacterium would also show reduced frequencies of base-pair substitutions while a mesophilic archaeon would not, and such organisms are now being investigated. In a separate line of work, we are investigating mutants that have more mutations than expected on a random distribution, and this area will soon be our major focus.

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Intramural Research (Z01)
Project #
1Z01ES065016-06
Application #
7169972
Study Section
(LMG)
Project Start
Project End
Budget Start
Budget End
Support Year
6
Fiscal Year
2005
Total Cost
Indirect Cost
Name
U.S. National Inst of Environ Hlth Scis
Department
Type
DUNS #
City
State
Country
United States
Zip Code
Kissling, Grace E; Grogan, Dennis W; Drake, John W (2013) Confounders of mutation-rate estimators: selection and phenotypic lag in Thermus thermophilus. Mutat Res 749:16-20
García-Villada, Libertad; Drake, John W (2013) Experimental selection reveals a trade-off between fecundity and lifespan in the coliphage Qß. Open Biol 3:130043
Drake, John W (2012) Contrasting mutation rates from specific-locus and long-term mutation-accumulation procedures. G3 (Bethesda) 2:483-5
García-Villada, Libertad; Drake, John W (2012) The three faces of riboviral spontaneous mutation: spectrum, mode of genome replication, and mutation rate. PLoS Genet 8:e1002832
Burch, Lauranell H; Zhang, Leilei; Chao, Frank G et al. (2011) The bacteriophage T4 rapid-lysis genes and their mutational proclivities. J Bacteriol 193:3537-45
Drake, John W (2009) Avoiding dangerous missense: thermophiles display especially low mutation rates. PLoS Genet 5:e1000520
Drake, John W (2007) Mutations in clusters and showers. Proc Natl Acad Sci U S A 104:8203-4
Mackwan, Reena R; Carver, Geraldine T; Drake, John W et al. (2007) An unusual pattern of spontaneous mutations recovered in the halophilic archaeon Haloferax volcanii. Genetics 176:697-702
Drake, John W (2007) Too many mutants with multiple mutations. Crit Rev Biochem Mol Biol 42:247-58
Drake, John W (2006) Chaos and order in spontaneous mutation. Genetics 173:1-8

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