Mutational robustness of ribosomal protein genes.
The distribution of fitness effects (DFE) of mutations is of fundamental importance for understanding evolutionary dynamics and complex diseases and for conserving threatened species. DFEs estimated from DNA sequences have rarely been subject to direct experimental tests. We used a bacterial system in which the fitness effects of a large number of defined single mutations in two ribosomal proteins were measured with high sensitivity. The obtained DFE appears to be unimodal, where most mutations (120 out of 126) are weakly deleterious and the remaining ones are potentially neutral. The DFEs for synonymous and nonsynonymous substitutions are similar, suggesting that in some genes, strong fitness constraints are present at the level of the messenger RNA.
Department of Medical Biochemistry and Microbiology, Uppsala University, SE-75123 Uppsala, Sweden.
Peter A
PA
Lind
Otto G
OG
Berg
Dan I
DI
Andersson
D001426:Bacterial Proteins / Q000235:genetics*; D005798:Genes, Bacterial; D056084:Genetic Fitness; D009154:Mutation; D020871:RNA Stability; D012329:RNA, Bacterial / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012269:Ribosomal Proteins / Q000235:genetics*; D012486:Salmonella typhimurium / Q000235:genetics* / Q000254:growth & development; D012641:Selection, Genetic
D001426:Bacterial Proteins; D012329:RNA, Bacterial; D012333:RNA, Messenger; D012269:Ribosomal Proteins; C028546:ribosomal protein L1; C029611:ribosomal protein S20