Stress-Induced Mutagenesis and Complex Adaptation
Yoav Ram, Lilach Hadany
doi: http://dx.doi.org/10.1101/007096
Abstract:
Because mutations are mostly deleterious, mutation rates should be
reduced by natural selection. However, mutations also provide the raw
material for adaptation. Therefore, evolutionary theory suggests that
the mutation rate must balance between adaptability - the ability to
adapt - and adaptedness - the ability to remain adapted. We model an
asexual population crossing a fitness valley and analyze the rate of
complex adaptation with and without stress-induced mutagenesis - the
increase of mutation rates in response to stress or maladaptation. We
show that stress-induced mutagenesis increases the rate of complex
adaptation without reducing the population mean fitness, thus breaking
the evolutionary trade-off between adaptability and adaptedness. Our
theoretical results support the hypothesis that stress-induced
mutagenesis promotes adaptation and provide quantitative predictions of
the rate of complex adaptation with different mutational strategies.
Keywords: Adaptation, stress, evolution
