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(Biology) biology an abnormally great change in the characteristics of a population of animals or plants over relatively few successive generations: hypothesized in the evolutionary theory of punctuated equilibrium, which states that such populations remain stable for long periods of time and evolve into new species through sudden, drastic mutations
[C20: from macro- + mutation]


(ˌmæk roʊ myuˈteɪ ʃən)

a mutation that results in a profound change in an organism, as a change in a regulatory gene that controls the expression of many structural genes.
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References in periodicals archive ?
Everyone agreed that Darwin's process could explain changes to the left of this point (microevolution), but some now argued that a fundamentally new phenomenon called genetic mutation or macromutation was responsible for the larger-scale differences to the right (macroevolution).
A macromutation in Tripsacum dactyloides (Poaceae): Consequences for seed size, germination, and seedling establishment.
In order to mantain diversity in the population they use two clustering techniques and a macromutation operator.
An argument for nonasymptotic increases in fitness, however, must necessarily invoke some sort of macromutation, or beneficial mutation of large effect, that bridges an adaptive valley.
It was suggested that the highly significant effect of the macromutation Es1 probably reduced the power for identifying other QTL affecting stearic acid levels (Perez-Vich et al.
We found no evidence to support the most extreme hypothesis that a single locus is responsible for the major differences between HV and HS in host use patterns; that is, there is no macromutation that might have caused a complete shift from a generalized to a specialized diet.
Two mechanism of macromutation are incorporated to the algorithm to maintain genetic diversity in the population.