Whole-genome mutational biases in bacteria. Export

@article{citeulike:3509109, abstract = {A fundamental biological question is what forces shape the guanine plus cytosine (GC) content of genomes. We studied the specificity and rate of different mutational biases in real time in the bacterium Salmonella typhimurium under conditions of strongly reduced selection and in the absence of the major DNA repair systems involved in repairing common spontaneous mutations caused by oxidized and deaminated DNA bases. The mutational spectrum was determined by whole-genome sequencing of two S. typhimurium mutants that were serially passaged for 5,000 generations. Analysis of 943 identified base pair substitutions showed that 91\% were GC-to-TA transversions and 7\% were GC-to-AT transitions, commonly associated with 8-oxoG- and deamination-induced damages, respectively. Other types of base pair substitutions constituted the remaining 2\% of the mutations. With regard to mutational biases, there was a significant increase in C-to-T transitions on the nontranscribed strand, and for highly expressed genes, C/G-to-T mutations were more common than expected; however, no significant mutational bias with regard to leading and lagging strands of replication or chromosome position were found. These results suggest that, based on the experimentally determined mutational rates and specificities, a bacterial genome lacking the relevant DNA repair systems could, as a consequence of these underlying mutational biases, very rapidly reduce its GC content.}, author = {Lind, Peter A A. and Andersson, Dan I I.}, citeulike-article-id = {3509109}, citeulike-linkout-0 = {http://dx.doi.org/10.1073/pnas.0804445105}, citeulike-linkout-1 = {http://view.ncbi.nlm.nih.gov/pubmed/19001264}, citeulike-linkout-2 = {http://www.hubmed.org/display.cgi?uids=19001264}, day = {10}, doi = {10.1073/pnas.0804445105}, issn = {1091-6490}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, keywords = {bacteria, bias, genome, mutational, whole-genome}, month = {November}, posted-at = {2008-11-25 13:14:56}, priority = {2}, title = {Whole-genome mutational biases in bacteria.}, url = {http://dx.doi.org/10.1073/pnas.0804445105}, year = {2008} }

TY - JOUR ID - citeulike:3509109 L3 - citeulike-article-id:3509109 N2 - A fundamental biological question is what forces shape the guanine plus cytosine (GC) content of genomes. We studied the specificity and rate of different mutational biases in real time in the bacterium Salmonella typhimurium under conditions of strongly reduced selection and in the absence of the major DNA repair systems involved in repairing common spontaneous mutations caused by oxidized and deaminated DNA bases. The mutational spectrum was determined by whole-genome sequencing of two S. typhimurium mutants that were serially passaged for 5,000 generations. Analysis of 943 identified base pair substitutions showed that 91% were GC-to-TA transversions and 7% were GC-to-AT transitions, commonly associated with 8-oxoG- and deamination-induced damages, respectively. Other types of base pair substitutions constituted the remaining 2% of the mutations. With regard to mutational biases, there was a significant increase in C-to-T transitions on the nontranscribed strand, and for highly expressed genes, C/G-to-T mutations were more common than expected; however, no significant mutational bias with regard to leading and lagging strands of replication or chromosome position were found. These results suggest that, based on the experimentally determined mutational rates and specificities, a bacterial genome lacking the relevant DNA repair systems could, as a consequence of these underlying mutational biases, very rapidly reduce its GC content. JF - Proceedings of the National Academy of Sciences of the United States of America SN - 1091-6490 TI - Whole-genome mutational biases in bacteria. KW - bacteria KW - bias KW - genome KW - mutational KW - whole-genome AU - Lind, Peter A AU - Andersson, Dan I PY - 2008/11/10/ UR - http://dx.doi.org/10.1073/pnas.0804445105 ER -