New Insights into the Molecular Mechanisms of Evolution
Stress Increases Genetic Diversity V. V. Velkov Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences. Pushchino. Moscow Region, 142290 Russia: E- mail: velkov@ibpm.serpukhov.su Received September 21, 2001 The mechanisms of stress-induced mutagenesis in prokaryotes and realization of reserved (preaccumulated) genetic variation in eukaryotes are considered. In prokaryotes, replication becomes error-prone in stress because of the induction of the SOS response and the inactivation of the mismatch repair system; stress also increases the transposition rate and the efficiency of interspecific gene transfer. In eukaryotes, chaperone HSP90, which restores the native folding of mutant proteins (e.g., signal transduction and morphogenetic proteins) in normal conditions, fails to do so in stress, which leads to abrupt expression of multiple mutations earlier reserved in the corresponding genes. The role of these mechanisms in the evolution of prokaryotes and eukaryotes is discussed.
