2001/03/01 by Lev Y. Yampolsky, Arlin Stoltzfus · 6 citations
Biochemistry, Genetics and Molecular Biology · Social Sciences · #Evolution and Genetic Dynamics #Genetic diversity and population structure #Evolutionary Game Theory and Cooperation
paper · doi:10.1046/j.1525-142x.2001.003002073.x
openalex publication_date 2001/03/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
According to New Synthesis doctrine, the direction of evolution is determined by selection and not by "internal causes" that act by way of propensities of variation. This doctrine rests on the theoretical claim that because mutation rates are small in comparison to selection coefficients, mutation is powerless to overcome opposing selection. Using a simple population-genetic model, this claim is shown to depend on assuming the prior availability of variation, so that mutation may act only as a "pressure" on the frequencies of existing alleles, and not as the evolutionary process that introduces novelty. As shown here, mutational bias in the introduction of novelty can strongly influence the course of evolution, even when mutation rates are small in comparison to selection coefficients. Recognizing this mode of causation provides a distinct mechanistic basis for an "internalist" approach to determining the contribution of mutational and developmental factors to evolutionary phenomena such as homoplasy, parallelism, and directionality.