The probability of improvement in fisher's geometric model: A probabilistic approach

Yoav Ram*, Lilach Hadany

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Fisher developed his geometric model to support the micro-mutationalism hypothesis which claims that small mutations are more likely to be beneficial and therefore to contribute to evolution and adaptation. While others have provided a general solution to the model using geometric approaches, we derive an equivalent general solution using a probabilistic approach. Our approach to Fisher's geometric model provides alternative intuition and interpretation of the solution in terms of the model's parameters: for mutation to improve a phenotype, its relative beneficial effect must be larger than the ratio of its total effect and twice the difference between the current phenotype and the optimal one. Our approach provides new insight into this classical model of adaptive evolution.

Original languageEnglish
Pages (from-to)1-6
Number of pages6
JournalTheoretical Population Biology
StatePublished - 1 Feb 2015


FundersFunder number
Israeli Science Foundation1568/13
Manna Program in Food Safety and Security


    • Fitness landscape
    • Mathematical models
    • Mutations
    • Population genetics


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