||Bacteria Escherichia coli
||Firnberg E, Labonte JW, Gray JJ, Ostermeier M: A Comprehensive, High-Resolution Map of a Gene's Fitness Landscape. Mol Biol Evol 2014. p.7 left columnPubMed ID24567513
||Bershtein S, Mu W, Serohijos AW, Zhou J, Shakhnovich EI. 2013. Protein quality control acts on folding intermediates to shape the effects of mutations on organismal fitness. Mol Cell. 49:133–144.PubMed ID23219534
||(primary source abstract:) "[Researchers] mutate the E. coli's gene encoding dihydrofolate reductase (DHFR) and replace it with bacterial orthologous genes to determine how components of PQC [protein quality control] modulate fitness effects of these genetic changes."
||"A ... study estimated that DHFR could
sustain an 80% cut in protein abundance with little effect
on organismal fitness and that the dependence of fitness
on protein abundance exhibited Michaelis–Menten-like
behavior (primary source)."